Skin Biopsy is a procedure to have a piece of skin taken out for microscopic examination, it is done for a diagnostic purpose usually when we are not sure what the lesion is, or try to find out the extend of the lesion (mapping) before surgery.
Biopsy is done under local anaesthetic (injection under the area where it needs numbing), therefore other than the first injection, you will not feel any pain during the actual procedure.
It is a quick procedure, and it can usually be done under a few minutes.
Attached is a photo of the punch biopsy tool. The diameter of this punch is 3mm, however, depending on the need, biopsy tool of different sizes are available.