Can acne cysts spread? must they be treated or will they go away? how often does this happen? why does this happen?

Rx cystic acne: I'm going to assume the diagnosis is correct. Cystic lesions may need a steroid injection from a skilled dermatologist. Regardless, having acne today is a sign of poor self-care and is a professional liability. Hopefully you are using a topical agent such as benzoyl peroxide, and you'll need a second prescription-strength rx as well. If offered isotretinoin, consider doing it. Best wishes.