I'll try to help you with your question if I can. (My disclaimer: I'm a dermatology nurse. However, your doctor's advice supercedes anything I or anyone else says here.)
Dysplastic moles are basically moles that show an abnormal cell arrangement microscopically. They are generally classified as mild, moderate, or severe. They are not considered pre-melanoma or a skin cancer. However, anyone with dysplastic moles is at higher risk of developing melanoma in general, anywhere on his/her body, compared to someone without dysplastic moles.
Because your daughter's moles were severely dysplastic, the doctor may prefer to treat as though they were melanoma as a precaution. Generally, the treatment for dysplastic moles and very early superficial melanoma is to make sure the entire lesion was completely excised with a standard margin of normal skin. When that's done, the patient must continue to follow up for routine skin exams to monitor for any changes in other moles, and they must also watch on their own between visits. They must also make changes to avoid unprotected sun exposure. That means DAILY sunscreen, reapply often when outdoors, and ABSOLUTELY NO TANNING BEDS!!!!!
There usually is not a need to see an oncologist for dysplastic moles. However, the doctor should be giving your daughter all of this education and specific instructions for her follow up care. If your daughter is not clear about her condition or what she should be doing, she needs to go back to the doctor and ask these questions. Knowlege is power.