Hi. Thanks for your query. Noted the history and understood the concerns. Crack in a butt cheek that is red and sore is usually due to inter-gluteal dermatitis as you are sitting long hours hence the sweat is getting accumulated causing sub-clinical infection and hence the further problems. Long sitting also causes the so called acne which is basically a problem of the skin due to infection and dermatitis. I would advise you the following: Get the blood test for CBC and sugar in particular. Clinical evaluation by a General Surgeon or a Dermatologist for a proper diagnosis and further management. Clean the area with plain water two to three times a day. Take an antibiotic if required. Apply liquid povidone iodine locally. Multivitamins help a lot in good healing. Avoid hot and humid atmosphere.