looks like you have developed folliculitis
( pyodermas) over the gluteal region
Folliculitis (also known as "Hot Tub Rash") is the inflammation of one or more hair follicles. The condition may occur anywhere on the skin with the exception of the palms of the hands and soles of the feet. They may appear as red dots firstly and then increase in size to become red , hot, tender pus filled lesions...
Avoid touching it too much...Avoid using any kind of cold
dreams or oils..as it might increase the lesion..Wear pure cotton clothes and undergarments in order to reduce sweating.
You can start using any topical antibiotic/antiseptic cream over the lesion and see if it persists even after using the cream for 2-3 days, then you need to consult a skin specialist who can assess the condition and give oral antibiotics
...Take some pain killers along for relieving the associated pain and discomfort
If you have history of recurrent development of such lesions, then get a random blood sugar analysis done in order to rule out Diabetes
Hope it helps
Dr Geetika Paul