Hi Dr. My Son Worked With Thinners Polyethemene And Three

Hi dr. My son worked with thinners polyethemene and three days ago he saw on leg red itchy pimples and at the back of hes ears and on arms. Its getting ugly even more. I gave allergex tabs and allergex cream and savlon to wash in bt its gettn worse pls what is it and can i go buy an over the counter meds. Thanx in advance. Yolanda Beukes.