Hi. so red itchy patch beneath belly button? what do i do?

Red patch: Without seeing this it is impossible to determine what it is. You can try a short course of over-the-counter topical steroid (hydrocortisone cream) to see if the area normalizes and the itching improves. If no response in 1 week or the area enlarges or changes then you should see your primary care physician or a dermatologist.

?nickel dermatitis: May be nickel allergy due to metal snaps coming in contact with your skin. Cover the inside of the snap with material and use a topical steroid on the rash. If not improving in 2 weeks see an allergist or dermatologist.