Hi. Thanks for your query and an elucidate history. Noted that your husband and you were on vacation in mexico. He started getting stinging, and burning in his mouth.It then turned into sores all over his mouth and tongue. The walk in doctor gave him an ointment to put on the sores for 4 days. He did not elaborate on what it is. Now he has sores on his testicles and groin area. He is in a lot of pain. Do you have any idea what it could be? This is suggestive of some infection that has affected the oral cavity and the scrotal area. Another possibility is that he has developed allergy to something and needs careful clinical evaluation and treatment with steroids and antihistamine and antibiotics to tackle or avoid the infection. Take him to the Specialist like an ENT Surgeon or Dermatologist.