Hello,
I cannot confirm without examination,but it can be due to fungal infections like
ringworm(tinea corporis).The other possibility is of nummular eczema.
Keep your effected area dry and keep a separate towel for yourself. Most forms of ringworm respond to over-the-counter products, which contain any of several basic ingredients: miconazole, tolnaftate, terbinafine, and clotrimazole.If still the symptoms persist then pls get it evaluated from a dermatologist.
Hope it helps.