I have a thick rash only on my left arm pit. What should I do? The rash is not one big rash. It is spred out in 4 different rashes & bright red.

Get the diagnosis. There are many types and causes of skin rashes. Several types of inflammatory conditions of the skin, allergic reactions, and sometimes bacterial, viral or fungal infections can cause rashes on the skin. Insect bites can also be the cause of a rash on the skin. Have it evaluated by a professional and get the appropriate treatment.