I have been on humalog at 10iu post workout for the past 5 weeks. Im coming off in another week. I only used like half the vial. What i was wondering is if i wanna go back on slin in 6 weeks, will the same vial be good if i keep it refrigerated, or do i need to buy a new one? Also, do i start right up at 10iu right away, or do i have to gradually work my way up again like last time?