PRP by itself will not cause inappropriate hair growth. Hirsutism is caused by hormone imbalances and dysmetabolism in PCOS. If underlying causes are addressed as you describe, facial hair in women will not regrow. PRP done for facial hair in men will only stimulate it in the areas where it grows normally.
Microneedling with just PRP should not cause any shock loss. Combining/stacking PRP with other agents will have a higher risk
Lidocaine can be injectable, not just topical, so you don't need to wipe it off. However, it is not recommended with PRP. Bupivicaine, tetracaine or marcane can be used in variety of combinations topiocally that can be made by a compounding pharmacy. They are also available as injectables.
One session is not enough. You want 4-8 monthly treatments, then follow up in a year. Every time PRP induces and supports a process of remodeling of collagen and renewing skin. One treatment will start the process, but depending on your age and skin condition you will need to continue to reenergize this process with subsequent treatments.
Yes. You could also have it done in one session. Usually injections first then microneedling with PRP
