Lore...You've hit upon a very important element of the narrative, the use of hyperbole which is present throughout the text but which increases dramatically beginning with the seventh plague. The hyperbole gets at the key mythological theme in the book -- the undoing of creation, the reverting of creation to primeval chaos at the hand of God, and his singular ability to restore creation. The hyperbole increases the scope of the disaster to a universal level, at least within the "land" ('rts, cf. 'rts in Genesis 1) of Egypt. So when every single speck of dust in the land turns into a gnat (Exodus 8:17), which partially undos the creation of dry land on the third creative day by turning it into living creatures (as in Genesis 1:24), imagine how great their numbers must of have been. Imagine how enormous the hailstones must have been in order to shatter every single tree (Exodus 9:25), and then when the locusts come to devour every single morsel of vegetation (ch. 10), this is a literal undoing of the creation of vegetation on the third day. The plague on livestock similarly gets rid of all the land animals created on the sixth day (ch. 9), the turning of the Nile River to blood undoes the creation of water from the land/water mixture of the "deep" on the third day (ch. 7), and the plague of deep gloom and darkness (such that even fire would not give forth light) of course undoes the creation of light and the separation of light from darkness on the first day (ch. 10).
These plagues (which are called "signs", i.e. they point forward to something) also anticipate the final act...the deliverance at the sea. The "sign" of blood throughout the water of Egypt in Exodus 7 foreshadows the deaths of the Egyptians in the sea (cf. 12:13, where blood specifically is a sign for deliverance). This is recognized in the reuse of this text in Ezekiel 32:6, which claims that the land of Egypt would be drenched with blood "and the watercourses will be full of you" (cf. "there was blood throughout all the land of Egypt" in Exodus 7:19, 21). The sign of the locusts similarly looks forward to the deliverance at the sea, they "cover" the entire land (10:5, 15) just as the sea covers the Egyptians (14:28, 15:5, 15), and they are all driven into the Sea of Reeds by the east wind (10:13), such that not a single locust was left (v. 19), just as the Egyptians with Pharaoh were driven into the Sea of Reeds (where the east wind had been keeping the waters together) where they met their ends (14:28). The plague of darkness prefigures the darkness that Yahweh brought the Egyptians while the Israelites were crossing the sea (14:20). The plague on livestock points foreward to the drowning of the horses in the sea (indeed, it is at tension with it, if the hyperbole is given due weight). The miracle at the sea, of course, utilizes the old Chaoskampf theme of divine war against primeval chaos, a theme that is recognized by Deutero-Isaiah (Isaiah 51:9-11, where the defeat of the dragon Rahab is equated with the drying up of the Sea of Reeds, cf. Psalm 74:13), which similarly links back to the creative act of creating dry land on the third day (Genesis 1:9-10). Indeed, the description of primeval chaos in Genesis 1:2 compares well to the situation at the sea during the miracle: 1) darkness over the sea, hiding what was happening from the Egyptians, 2) God's wind blowing on the surface of the sea. Just as there was a clear division during the latter plagues between what was experienced by the Egyptians and what was experienced by the Israelites (such that the Israelites did not suffer darkness, the death of firstborn, etc.), so it is at the sea. On the side of the Israelites, God was creating dry land for them -- conquering the forces of chaos, whereas on the side of the Egyptians, they were not able to perceive what was happening on account of the darkness. And the Chaoskampf theme seems to present in the first sign performed, Aaron's staff swallowing up the Egyptians' staffs (7:8-13). The verb bl' "swallow" in this text next occurs in 15:12, where it refers to the swallowing up of the Egyptians in the sea, and God "stretches out his right hand" to act just as God works through Moses when he stretches out his staff (7:15, 14:16). Most interestingly, the word tnyn "dragon" occurs in the text (rather than the ordinary word for serpent), such that God uses a tnyn to defeat (swallow up) the Egyptian tnynym. This evokes God's use of the sea (= Yam, the dragon of the sea) to defeat the Egyptians, while at the same time showing his supreme mastery over the sea, i.e. over chaos. That Ezekiel uses tnyn as a symbol for Pharaoh (29:3-5, 32:2) shows some recognition of this symbology.
Then, in the subsequent wilderness narratives, God acts out a reversal of the plagues for the benefit of the Israelites; in other words, the plagues not only look back to the creation of the world and forward to the exodus, but they also look further ahead to the wilderness wanderings. This could be understood in Chaoskampf terms as well....after victory comes creation (or re-creation). So in 15:23, the Israelites learn that "they could not drink the water", which is anticipated by the transformation of water to blood such that "they could not drink the water" (7:24). For the benefit of the Israelites, God makes the water sweet and drinkable, and in fact fills the wilderness with water springs (15:27; cf. the use of the staff in 17:5 which connects the provision of water to the "striking of the Nile"). Similarly, there was a "rain" (mtsr) of hail on Egypt that destroyed all vegetation and food (9:18, 23), whereas after the exodus God brings a rain (mtsr) of bread from heaven (16:4). Again, the east wind blew and locusts came up ('lh) that covered (ksh) the entire land of Egypt, thereby destroying every morsel of food, whereas the wind blows and brings quail (a food source) instead of devouring locusts (10:13). And whereas God brought all sorts of diseases to the Egyptians, he declares to the Israelites in 15:26 that he would heal them of any disease.