Once my mother had to stand on freezing cold dirty water for hours due to some reason. Since then, she has been experiencing some disorders in her toenail. After some days of the incident, her nail turned yellowish in colour Several days later, her nail turned dark brown in colour After some days a part of her nail started to crumble A few days later, her toenail fully turned into a mixture of yellow and dark brown Now, her toenail is a little sticking out like a lump Please suggest me what to do