Is a technician supposed to wipe my face after PRP microneedling?

Usually, the skin is cleansed (e.g. wiped with chlorhexidine) before such a procedure, but not afterwards, as there might still be some PRP on the skin surface and you don't really want to be wiping it off. Sometimes there is excessive serum visible on the skin afterwards and this excess could be gently dabbed with a clean dry non-woven gauze pad. Most PRP is absorbed quickly into the skin during the procedure, so even if the skin was wiped after the procedure, not much PRP would be removed.
Ideally, after proper microneedling and PRP application, the skin should be light red, with no visible bleeding. A lot of the pictures found online appear too aggressive with visible bleeding. (e.g. the famous KK photo which brought widespread attention to the Vampire Facial). In my opinion, such treatment causes too much trauma to the skin and may potentially lead to excessive inflammation or worse, scars. Make sure the microneedle device is safe and licensed by the FDA or Health Canada to avoid the risk of cross-contamination from blood getting inside the machine from another patient.
The quality of the PRP is also very important and should be derived from an approved kit. In my opinion, platelet-poor plasma (PPP) should not be used afterwards, as some studies have shown that it may contain inhibitors which reduce the concentration of growth factor release from PRP. However, there is still debate about this point and the research is still in relatively early stages.