My dog had a reaction to frontline and has lumps now that matter and bleed ,how do I treat this?

Are you sure it's the frontline? And not something else?

Benedryl works great for hives. Its 1mg per 1 pound of body weight. Typically benedryl comes in 25mg tabs. When purchasing the benedryl, ensure that there is no other ingredients added and is just diphenhydramine.

Wash your pet in cool water dawn dish soap to help get the oil off. You may have to wash her twice.

Any strange reactions or changes in behaviors should always be consulted with a vet.