It sounds like hemorrhoids with a yeast infection caused by moisture. This is a common situation. Treat the digestive problem (constipation usually) and treat the itchy spot with Lotrimin cream. Use baby wipes to clean after going to the bathroom when possible.
Hello,
If it is on the top of the butt crack then it can be a pilonidal dimple as well. The majority of pilonidal dimples are harmless, congenital anomalies that consist of a small depression or pit. There may be increased hairiness around the area.
The pilonidal dimple may also be a deep tract, rather than a shallow depression, leading to a sinus that may contain hair. These can become infected and drain.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.