It may be a syst. Which is just a boil of pus under the skin I know gross but if you are worried just take her to the vet. My dog had one and my mom ignored it. He died September 19,2007. R.I.P.

NNNNNNOOOOOOO it will make them sooooooo sick just put ice on it and if the stinger is still in don't rub it . It will be pushed out when it's ready.