What can be done to make hair grow back after acne medication causes bald spots?

The combination of PRF (Platelet-Rich Fibrin) and exosomes could be a promising option for treating your son's condition. PRF, with its high concentration of growth factors, can help in healing the scalp and potentially stimulate hair growth. Exosomes, which are cell-derived vesicles, are known for their role in cell communication and can significantly aid in tissue repair and regeneration.
This combination therapy might address both the healing of acne-affected areas and the promotion of hair growth in bald spots. However, it's essential to consult with a dermatologist or a healthcare professional experienced in hair restoration treatments to evaluate your son's specific condition and determine the most appropriate treatment plan. They can provide tailored advice, considering the severity of his acne, the extent of hair loss, and his overall health.

There is a very strong likelihood that the areas of hair loss associated with his comedones/acne lesions are from picking at them and not from the medicines. It is CRUCIAL that he not pick, pop or otherwise handle his acne lesions. Once he has caused a scar to form, the hair will not grow back in that area. He should see a dermatologist for further care for his acne and once it is fully resolved, a transplant may help replace the hair that has been lost in those areas. I hope this answers your question.