It's most likely a hemorrhoid. It's when your blood flow is cut off and swelling occurs, a hard lump is normal to be found inside one. They can be caused by straining while pooping, anal sex, obesity, and lifting. Get preparation H or a hemorrhoid cream that comes with an insertable nozzle as yours is on the inside. Also eat lots of fiber even if straining wasn't the cause you don't want any whatsoever as it will make it larger.
Hi, understand your predicament. But it is difficult to tell what the lesion unless examined. It could be a tumor, a thrombosed pile mass or a fistula. You will need to consult a doctor, who will do a rectal exam and proctoscopy to see the lesion. He may then take a biopsy, A biopsy facilitates a histologic study of cells, which gives you a definite diagnosis. So once you have the diagnosis you will know what measures or precautions you need to follow. Good luck. Regards.