URGENT - Guinea pig help!?

I have had a guinea pig before and it seems to me that she is suffering from a rash/inflammation from her...well you know.And i would take her to the vet cause it could be Very well serious and it and even though im not a vet or an expert she needs an appointment at your local vet.If not go to the store where you got her from and see what the Guinea pig person says or the person on the rodents section.maybe he could tell you whats wrong