I injured my big toe three months ago at the gym kicking a punching bag. the toe nail is still very bruised but it doens't hurt. how much longer heals?

6 months: Toenails take nearly 9 months to grow from back to front, so if the injury happened 3 months ago, you still have a half year until the bruise underneath completely resolves, assuming it started at the very back of the nail.

Bruised toenail: Bruising of the toenail after trauma can be cause from bleeding that occurs below the nail and is into the nail bed or skin under the nail. If the dry hematoma is attached to the nail, it will usually 'grow out' as the nail grows in length. This can take from 3 to 9 months.

Diabetic Warning: It can take up to 11-12 months for a toenail to fully grow out. If your diabetes is uncontrolled or if your circulation is less than optimum, healing can take longer. If the nail was severely traumatized, it may separate from the nail bed and eventually fall off. Since you're diabetic, see a podiatrist to make sure your toe is not at risk for infection, rule out neuropathy, prevent amputation.