Common wart removal (salicylic acid). should the healthy skin be painful when applying the acid? needled&clipped the small wart flat then applied, then some skin came off with tape but no black thingy or hole in the middle and not sure when to stop?

Some basics: A wart is something like an iceberg, with a significant portion under the waterline (skin surface). It is also like an onion with many layers & a root system. Whatever the treatment, to be successful you must get all the wart above/below skin line and the root system. You will usually create a bloody hole in your skin if you go far enough to get it all. Sounds like your not deep enough. Keep going