Halo treatment 4 days ago. Corner of mouth seem infected. Any suggestions?

Hi and thank you for your question. Definitely give the office a call regarding this issue. If you have a history of cold sores, you will likely need an antiviral oral medication to resolve this. It is not uncommon in someone with this history. Best, Dr. Grant Stevens

I would recommend you contact the physician who performed the treatment for an evaluation.  The redness could be dry skin, a cold sore or an early infection of the skin.  It is always better to be safe and be evaluated instead of letting something worsen over time.

A photo will help narrow down a treatment if this is truly an infection. Avoid self treating and follow up with your  doctor to see what the next step is for you.