Welcome to icliniq.com.
The hard nodule bursting on your buttocks was an infected sebaceous cyst. If recurrent on the same spot, you may need a small surgery of cyst excision. For eyes, get refractive error checked and if needed specs. Burning urination is with poor flow, straining of urine? How many times you get up at night. Kindly get urine analysis and USG KUB and share the report to suggest treatment.
For itchy perianal area sit in a warm sitz bath for 15 minutes, if persistent, show to a general surgeon. Black patch on the penis can be commented only after seeing the picture. Smegma under prepuce is a white deposit and you daily need to retract the prepuce and wash it with water during bath.