wow, everyone here is over reacting.
yes, you can finish the season. if you are smart.
cross training only through the rest of the season. at least 100% cross training this week. the next two, you can run workout days only, warmup/cooldown on the bike or elliptical. then rip it your last few races. the fibula is only 10% weight bearing. a few more weeks of minimal running is not going to make it worse.
after the season is over, you need to take 4 weeks off. no running, no cross training. wear supportive shoes around all day every day these upcoming weeks too, no heels or flats. wear your running shoes. no, a walking boot won't help for this particular bone and crutches are unnecessary since its only 10% weight bearing.
don't foam roll on it, but you can use the stick. ice and ibuprofen.
when you are cross training, cross train your little butt off. get your HR up high. don't lose all the fitness you worked so hard for. you just need to bike or elliptical or swim. cross training should "feel like a workout" every day and should not be taken lightly. do at least 60 minutes, and try to get 90 minutes about twice a week.
literally just got told i have a fibular stress fracture but my sports doc recommended the above to finish the last two weeks of my season. good luck.