My mom is a painting maniac. She paints the house so much, and even painted the ceilings of an apartment (my parents own a couple of garage apartments that they rent out) while she was pregnant. Anyway, she has brown hair and always looked like it had snowed on the top of her head
If there are a few splatters and spots on strands of your hair, get a good nail polish remover and soak two cotton swab tips in it, and then slide your hair in between them until it comes off. If it's a lot sometimes it won't come out very easily, and then after you get the peice saturated use your finger nail to kind of scrape the layer of paint off. Be careful not to do it too hard and damage your hair.
If it's an especially glossy paint than this doesn't always work

In cases like that, the only way to get it out would be to use a DAB of paint thinner (eeek I know) on a cotton swab. Be careful not to use too much because that stuff is strong, A dab should get the spot away fine, and then be sure to rinse it out. Also, make sure to do it in a well ventilated area or it will really give you a headache.
Good luck! Paint in your hair is the worst!