Hello. Welcome to ask the doctor.
I understand your concern.
If your half of the nail has fallen off, then there must be some reason behind it. It is most often due to sudden trauma to the nail. In such cases, the skin under nail becomes sensitive and pains on application of pressure.
If it is due to other causes like Paronychia, lichen planus or psoriasis, then it is usually painless.
You can put socks over it preferably after applying a gauze piece over affected nail.
I will advise you to visit your doctor so that he can examine you and come to final diagnosis.
I hope I am able to solve your query.
If you have any further query, you may ask me.
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.