I Can't Work Out If It's A Pimple Or A

I can't work out if it's a pimple or a whitehead etc - it is on my bladder basically and was fully red quite small and when I pressed it hurt - it's been a week and there's a white little dot very tiny on top of it and when I press it's not sore any more - today I lied down and the pimple or whatever it is on the left side hurt my stomach on the inside like there something inside of me. I'm very confused please help