Hello dear, The lump as mentioned in your post can be attributed to fungal infection. Management includes: 1. Keeping the area clean, dry & avoid too much exposure to water or sweat formation. 2. Antihistamine preparations like cetirizine to reduce the itching sensation & provide symptomatic relief. 3. Application of topical antifungal ointment like Clotrimazole to tackle the causative organism. If symptoms still persist or aggravate further, then it will be better to consult a Dermatologist & get a proper examination done to find out the actual cause. So that appropriate management steps could be taken. Wishing you a Good Health. Take care.