@turquoise-- I had to have a part of my toenail removed a few years ago due to a chronic fungal infection. The infection was not responding to any type of treatment and had caused my toenail to change in appearance and shape. My doctor felt that the best treatment option was removing the diseased part of the nail and letting a new fresh nail grow out.
The procedure wasn't painful because the doctor used an anesthetic. There was some discomfort for a few weeks afterward but there was no issue after that. Depending on how much of the nail is removed, it can take anywhere from a few months to over a year for it to grow back. Since I only had a part of my nail removed, it took about six months for that part to grow out and look normal again.
I don't regret it though because the treatment finally got rid of the fungal infection that I had been dealing with for so long.