How long should grade 2 ankle spain with low micro fracture of fibula take to heal?

6-8 weeks.: What do you mean "heal"? Bone remodels over a course of a year. A stress fracture heals just the same as a complete break given the same environment. You having 2 conditions, treating the fracture with immobilization will help both problems. For every week you are immobile, it takes about 2 weeks to get it back. So, if you have been laid up for 6 weeks, it will take a good 3 months to get it back