hi you seem to have developed Candidial Balanoposthitis.... ie Fungal infection of the glans and prepuce...Such infections are quite common especially when someone has been on antibiotics recently... Such infections initially present with collection of whitish discharge under the foreskin and later there is development of erythema, small white lesions and erosions over the affected area...and in later cases, it becomes difficult to retract the prepuce due to fissuring involving the prepucs.. So firstly , i would advise you to keep the area clean,..Try retracting the prepuce slowly little bit each day and do warm saline compresses over the region. After cleaning, apply a topical antifungal cream like clotrimazole cream over the affected area twice a day...try this for a week ,if there is not much relief then you might need oral antifungals as well...so visit a dermatologist for proper assessment and treatment if there is no relief hope it helps Dr Geetika Paul