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.
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.