Damaged blood vessel cut off circulation to the hair follicle how can I repair the blood vessel?

You can't. There is now way to repair small vessels. They just have to heal naturally. The vessel will either regrow or it won't.

Related Questions

I have several hair follicles filled with blood due to being connected to all blood vessels on my scrotum. Anything I should be concerned with?

Needs evaluation... This is something that certainly needs to be looked at. Not sure if these are really follicles inflamed but it could also be veins interconnected, among other issues. Make an appointment with your doctor or Urologist for examination.
Likely benign. It depends on how long you've had them and if you have anything similar on other parts of your body. Also would want to know if you have any bleeding disorders. But from your description, these sound like angiokeratomas of the scrotum, which are completely benign. I would recommend evaluation by a dermatologist for confirmation.