I have a red rash on my hand and knuckles its dry and burns. i think it's a allergic reaction. how long should i wait to see if it goes away. ?

7-10 days?: but it is hard to say since it depends much on how severe the reaction has been. Most hand dermatitis are from irritant (soap, detergent, machine oil, frequent washing, frequent hand sanitizer usage etc) Try some topical hydrocortisone cream for a few days and use only unscented soap. Apply hand lotion often especially after washing hands. See dermatologist if not helpful.