Never with my first BP, only once with my current one at about 750g and 3', was watching TV with my cat, then afterwards went to put my snake in a tub to clean the cage, probably combo of weird scent and startling, felt like a gentle headbutt, was shocked to see tiny droplets of blood in a semi-circle on my hand, 5 minutes and a good wash later couldn't even see any marks on my skin. There is a possibility of infection, so cleaning with anti-microbial soap is a good idea, also washing hands BEFORE handling a snake if you have been handling other pets recently, and taking care not to startle the snake with extra care anytime rodents or food is anywhere near. There really isn't any pain, definitely nothing that lasts, it's the surprise that gets you, just like getting zapped by static electricity in the winter. The tiny needle teeth might barely break skin, but snakes produce an anti-coagulant, so if you bleed, it looks ridiculously worse than it really is. Worst I ever had was a tag to the arm from a buddy's big red tail boa I was helping with, got hit as the snake was pulling back, it stung pretty good at first like getting snapped by a rubberband, had a few tiny pinholes and a couple that ripped and scratched on the surface, looked like pro-wrestling bad, running blood dripping on the floor, literally 5 minutes later, and nothing, no pain, no blood, just a couple tiny scratches and pin pricks. IMO a hamster has a BP beat on it's potential to injure you with a bite, and unless you are talking about a full grown retic, or getting tagged in the face you really have nothing to worry about.