It definitely sounds like you are HIV-negative. The rapid test for HIV is considered to be conclusive at 3 months. I would not recommend any further HIV testing.
Health concerns like dermatitis and pain in groin or arm pits are not generally symptoms we see associated with HIV. Pain in the groin can be associated with other STIs, and is a serious concern. If untreated some STIs can damage the reproductive organs and cause infertility.
We would recommend going to see a health care professional about your symptoms as soon as you can.
Hope this helps, please feel free to comment below or submit another question as needed.