does scalp biopsy cause hairloss and is it painful?

I've had a scalp biopsy before. The specific spot they cut will have a scar and if it's a large area and you keep your hair extremely short, then you might be able to spot the specific spot, but generally speaking, no. It won't case hair loss. I honestly don't even remember where they cut me. They should also give you a little shot of numbing agent, so it shouldn't hurt much at all during and then afterwards it's just like any other incision.

No biggie, and generally always well worth it if your doctor thinks they seem something worth cutting off.

Shouldn't cause hair loss at all. Think, if you cut your scalp doing stuff, does that cause hair loss; no. Stress can trigger hair loss so anxiety over getting the biopsy could mildly contribute to hair loss. I've battled with the road, dirt, rocks, and cars on a bicycle and been involved in insane crashes where I lost a lot of skin including my face and head. I always wear a helmet, but have had damage from glass inside and all around and can say that never caused hair loss.

Pain is relative and different for everyone. I have never had a biopsy, but I can say that nothing that is done in a hospital or medical environment is a really big deal, at least anything I have experienced. However I break bones like ribs in a crash and still ride my bike home for a dozen miles like a badge of honor.