well she has more then just one, so I dont think its a blister. And if you press on it (it's not painful to her) then it spreads and seperates more shed skin, so the oil in between the two layers actually makes sense. I'm giving her a soak since her tank is a little on the dry side right now and then I'll wait for her to shed on her own and let you all know how it goes.

It's just wierd though, 19 years of having snakes, I've never seen that. Although my snakes are taken way better care of then this was had been. Poor thing, Im glad she is with us now where she will get the care and love she obviously needs.