You went to the hospital. Are you sure it's a birthmark If it's Ota's nevus, I suggest you treat it with laser, because it feels ok after operation, but it will hurt a little. This is done in stages. Generally, hospitals and beauty hospitals with regular birthmarks calculate money by area, which can't be done at one time. It depends on the degree to which your skin absorbs photons. Actually, I suggest you go to the hospital more often. Compared with the cost performance, my area is relatively large, and it is more expensive to make Annex II.