It is common for skin to sometimes react to topical treatments. Since mometasone is a strong steroid, using it for 15 days might be causing irritation, or the underlying condition may need a different approach. Please consult your dermatologist to re-evaluate. They might suggest stopping the mometasone and trying a non-steroidal anti-inflammatory cream like tacrolimus, or switching to a milder topical steroid. If a fungal infection is still active, an oral antifungal like fluconazole or a different topical antifungal might be considered. For immediate relief, apply a cool compress and a gentle, fragrance-free moisturizer. Do not worry; adjusting your treatment plan with your doctor will help soothe your skin safely.