Is it itchy can you describe the rash, any other symptoms?
Hello and hope you are doing well.
The rash could be due to contact dermatitis, that is exposure to an irritant like a chemical or metal or anything you are allergic to, it can cause rash. It could also be due to scabies, impetigo or sometimes due to herpes zoster or chicken pox. But to exactly pin point the pathology you will need to consult your primary care physician who will examine you an may ask for blood tests. If the need arises he may refer you to a dermatologist.
Hope this helped and do keep us posted.