I am worried about my ball python. I think there's something wrong with his vent.?

My snake is 3 or 4 years old, and he's had no health concerns up until this point. His vent looked a little swollen but then I bathed him in warm water and he pooped and it went away but now his vent doesn't look right. In between his spurs is kind of whitish and pasty looking. His poop is more liquid then a solid. Does anyone know what I can do or what it is or why it's happening?