What should I expect at the dermatologist?!

Yes, you can leave your bra and panties on unless the moles are underneath. I went to the dermatologist for the mole on the top of my head, but they also checked everywhere (not under my boxers, but everywhere else). It also doesn't take long and most moles should be harmless. Don't worry.

you certainly wont have to take your bra and panties off. especially if you're uncomfortable with it.

The dermatologist will likely focus their entire attention on the mole in question... dont get worked up about it. And if she can... bring your mom with you... as much as you may dislike her for making you go there in the first place... she's probably the best person you could have with you!

a woman doctor may make you feel better. see if you can get one. you won't have to take bra and panties off, and even if the mole was there, they'd just have you roll it down or up and wouldn't make you expose yourself.