You should talk to your doctor
. It is difficult to know what is going on without more description.
Sometimes, a contact allergy or contact reaction can develop. This occurs when the skin comes into contact with something that provokes a reaction, such as a new soap or laundry detergent. You should think back and see if you can associate the development of the rash with any particular new exposure. If so, you should discontinue the product. Itch can be controlled with over the counter antihistamines and steroid creams.
Another possibility would be folliculitis, a form of skin infection cause by infection at the base of the skin shafts. It is usually mild, and it can usually be controlled with good skin hygiene with an antibacterial soap and maybe some topical antibacterial ointment.
If there is any large area of spreading redness, warmth, or pain, or if you have fevers, these may be signs of a more serious type of skin infection and you should seek more emergent medical evaluation and treatment.
Other wise, you should set up an appointment with your primary care doctor
, who will be able to help you diagnose what is going on and what treatments are needed.