For a while, I thought I had cut a tendon or something because my finger could not be entirely straightened. This cleared up by itself within 6 months, however. I can then operate on my finger for a hour or so. The fingernails treated this way seem to grow slower than normal. As mentioned above, this may be somewhat permanent.
Some special equipment is required for some of the options as described below.
At this point, cut with scalpel or razor blade along the skin at each side of the nail starting near the tip and moving towards the base of the nail. This cut should not cut any nail, just skin. If you can get it down further, go ahead. Now peel back the flesh above the nail using a tweezers or pliers as far back as it will go. Keep a constant pressure on the skin as it takes some time for the flesh to come loose from the nail or nail bedding.