After reading your history it appears that your husband has developed simple folliculitis
. These areas are very prone for getting secondary infection specifailly in diabetics.
You can apply an antibiotic cream such as gentamycin cream. Antibiotic tablets
are must such as ciprofloxacin
or cefadroxil under medical advise. You can take pain killers tablets such as paracetamol
or diclofenac. If itching is present then can take benadryl accordingly.
Do not worry he will be alright soon. I advise you specifically to not pinch or pop the area and keep his sugar level in control.