How do i treat the skin symptoms of an amoxicillin reaction without medication?

Stop taking it: If you get a rash from penicillin, you should stop it immediately. You can take Benadryl (diphenhydramine) or another antihistamine like Claritin or zyrtec. If you insist on not taking any medication, then a cool shower or oatmeal bath may help with the itching. In any event, if you have any breathing problems, you need to go to the er.