I'm sorry to hear the student health center was not helpful! I had a good experience seeing my university health center for a suspicious mole.
In college, I had a mole that I thought had gotten bigger. When I went to the student health center, they removed the mole and tested it, and it turned out to be nothing. I hope you have the same result when you see the derm.
ETA: I hope that didn't come across like, "Your student health center is a piece of crap!" I wanted to convey, "My student health center was great, and I was hoping yours would be too so you wouldn't have to keep feeling worried."