How Should Knee Skin Rashes With Itching And Spots Be Treated?

Hello, My husband and I recently went snorkeling in the Caribbean and we brushed against the coral reef. Immediately the area started burning. Then after that it became itchy. We have been taking benadryl and a mixture of hydrocortisone and neosporin and my husband's rash is basically gone. However, mine spread from my knee down to part of my leg. Now I have red dots on my leg in addition to the original rash on my knee. The original rash came through my bathing suit which was covering my knee. Thanks