Thanks Mary for asking your question on Healthcaremagic.
Symptoms like public hair, acne
on forehead etc at this age is not normal. Your son suffers from what is called as 'Precocious puberty' (simple means early onset of puberty).
This is due to early release of pubertal hormones or extra production in the body.
I would advise you to seek opinion of Endocrinologist/Pediatic Endocrinologist (doctor specialising in hormonal
problems) as he would need to have few blood tests to check hormone levels, scan of his abdomen etc and then deciding what treatment is needed.
Please revert back to us with the results so as to guide you further.
Dr Tejas Shah