I have massive shedding PO PRP treatment with injection gun using a 31g needle at 10mm depth, did they damage my hair bulbs?

you m yhave telogen and need IM steroids or steroid injections. regardless you need acell with the prp and you should be on oral supplements, topical growth factors, and restorsea spray (see link).
I suggest a formal consultation as there are a combination of treatments that can be done to improve har loss.  Oral finesteride has very little to no side effects in the majority of people; PRP/platelet-rich plasma + stem cells like A Cell help regrow hair and slow down the thinning process; rogaine and restorsea spray should be used daily; oral viviscal helps keep nutrients high in the follices as well.  Transplantation is a last resort but works early in the aging process as well.  A formal consultation and combination treatment is needed.  Best, Dr. Emer.

Hair loss can happen after PRP. No, it’s not from damage to the bulbs. It’s usually from the massive numbers of growth factors and blood borne factors that cause the hairs to leave the scalp in some people. Your changes however are unusual so you’ll want to speak to the doctor and have the area examined. The timing of the loss and the amount of loss are unusual. But no, it has nothing to do with “damaging the bulbs.”