Thanks for your query.Based on the facts that you have posted it appears that you have
what is called as Sebaceous Cysts on scrotum
and back and ring worm infection
in the groin and armpit.
Please consult qualified general surgeon
for clinical examination .If needed it may have to get excised under local anaesthesia.
As regards treatment for ring worm
infection please apply anti fungal jelly like Meconazole twice daily for a week.
Observe proper personal hygiene by cleaning the arm pis and groin with warm water twice daily.