Acne treatment creams ok for superficial pore infection. Laser treatment and prescription (oral) antibiotics typical for a chronic infection, which you have. Unless you are a dirty person, having a persistent infection for 4 months puts you in the chronic category.
Advice from one agent is to not bother to apply for anything more than a 2 month stay (even though a 6 month visa is issued). If the applicant has zero travel history, it might also help by getting some immigration stamps from Hong Kong, Singapore or Vietnam. Not Laos though.
The IDP is basically a transcription of your driving licence. It's issued in your home country. Thailand updated to the 1968 convention which gives you a 3 year permit or to the expiry of your home licence, whichever comes first.