i would say it depends on the bite. i have had snakes bite me then just let go. i have had them "try" to let go but get stuck. just gently help them work free.

never ever ever pull a snake off you! if they dont let go just gently work their mouths forward to unhook the teeth.

i always expect to get bit. even from my snakes that have never shown any signs of aggression what so ever. i do this so that in the event i do get tagged i dont jerk my hand back so hard it hurts the snake.

ive kept snakes for 20 plus years, have worked in a large private pet store where they bred various species, and have spent time locally herping. i have been bit numerous times. more than half of those bites was my inexperience reading the snake. sometimes it hurts pretty bad but more often than not im surprised at how little it does hurt. so dont be too worried about it. hopefully it never happens to you but its part of game if you wanna keep snakes.