Exposed to lice

Ugh I'm itchy just thinking about it. If I've been exposed to lice at my job is there a good chance I've got it? There are about 5-6 people there who have it. My aunt who is a hair dresser checked me and said she didn't see anything but dandruff but I am now reading things that say it could take up to 4-6 weeks to appear? Should I go ahead and treat myself even if it doesn't look like I've got it?