What is the nature of the dry, slightly raised part of the toe, and does it affect the validity of ablution (wudu')?

This person is suffering from many obsessive thoughts, and he must turn away from these obsessions and completely ignore them. As for what is on the finger, if it prevents water from reaching the skin, and it is dead, dry skin that can be removed without pain, then it must be removed, and ablution is not valid with it. But if its removal causes pain, or if it does not prevent water from reaching the skin, then its removal is not necessary, and ablution is valid with it.