It's possible that it just hasn't started to spread yet, and then of course it's possible that that's not what it is. I've been fortunate that I've never seen it in person and never had to deal with it. It may even just be a reaction to the oil. I'm with Boger though, I think your best bet is to see a herp vet and just make sure it's not something that requires some type of treatment. Best case you get some peace of mind and she gets a check up, worst case it turns out to be something bad, but either way at least you know and can get some help with it.
I'm hoping it's just a "leave it alone and it'll resolve" type deal, but I'm just not sure and I'd hate for it to spread and you lose her over something that's probably treatable.