I fell on my ankle on the way to school.?

A few months back i sprained my ankle really badly and i was walking to shool about 45 minutes ago when i fell on my ankle. It hurts and its slightly swollen. Im back at home now. I cant get in touch with my mom, shes at work, im supposed to be at school now but it hurts to walk on it. What should i do? Should i go to school or wait for my mom to ring back? Nobodys phoned school to tell them i wont be in.