I am a medical cannabis patient in Oregon. There are a couple of good websites www.oregongreenfree.com and www.overgrow.com. The first is primarily a support group for legal carded patients and caregivers/growers (in Oregon) but there is valuable information there. The other site is more "pot-head" oriented but lots of info there, too.
MC - Medical Cannabis - does not have to be smoked to be used. I use what is called a vaporizer... (HerbalAir brand) it heats the herb to a precise temperature (I like 360degrees f) and releases the cannabanoids without releasing all the other toxic chemicals like tar and carbon monoxide you get from smoking. The vapor is inhaled. This is some of the easiest way to control ingestion as the results are nearly immediate and it's more difficult to overmedicate. Other ways include canna-butter and oils used for cooking, even tinctures and salves. The cannabanoids are oil- or alcohol- soluable - NOT water soluable.
I don't think just a poultice of ground up MC will do anything, as it requires a solvent (oil or alcohol) and/or heat (over 250 degrees) to release the cannabanoids.
Salves can be made by heating quality grown and cured MC (trim is just fine - buds are better vaped) with cosmetic or food grade skin oils like Olive, Almond, or Coconut, and blending in cocoa butter to help thicken it. Heated on the stove at a low temperature for several hours, then straining and squeezing as much oil out of the mess as possible. A potato ricer works great!
Long before I started using MC I studied medicinal herbs including how to make and use tinctures, salves, teas, etc. If I can be of further assistance please PM me and I'll give you my email.