As I mentioned before this is an acne nodule.
Ideally I would have treated it by injection of a triamcinolone acetonide
) in a concentration of 2.5 mg/ ml, 2-4 units, with a 26 G needle. Thereafter, it would settle down within 48 hours.
I would suggest that you take him to a dermatologist
who would administer it. The steroid has to injected into the nodule. The procedure is simple and there is only a minor pain.