Hi, I Noticed A Small Bump On My Inner Right

Hi, I noticed a small bump on my inner right butt cheek, immediately above my anus, several days ago and even though it wasn't causing discomfort at the time I started doing sitz baths. It has quickly grown in the past few days and is now the size of a walnut. It is skin colored/ a little red (I assumed because it is large and inflamed). There seems to be no sign of a white head and it is pretty firm, maybe slightly soft after a bath. However it is extremely painful. I have tried applying preparation H ointment along with the baths and cannot seem to find any relief. I am not sure what exactly this large painful lump is but I was thinking maybe external hemorrhoid? Please help!