Without a proper evaluation and diagnosis, it is difficult to understand the cause of the problem. I suggest taking your mother to a right doctor. Based on your mother's medical history and certain evaluations, he will be able to know the cause of burning feet and hands and can suggest an appropriate treatment. Hope this proved helpful. 

The boil-like structure could be a symptom of an infection. Pain and irritation while urinating are the most frequent. These include antibiotics or antifungal creams to help with the infection. The area should be kept clean and dry for a quicker recovery process. Drink lots of water and do not use strong soaps on the wound. 

It is safe to use a friend's derma roller after disinfection if it has been sprayed with alcohol. HIV is a sexual infection; sharing needles is one of the transmitter. A sterilized roller is thus no cause of fear or stress if someone else has got HIV. Such sterilized tools do not risk transmitting HIV.

White patches on your shaft are around sometimes because of a fungal infection called candidiasis or a disorder like lichen planus. These can show up after sex, especially if unprotected. These can be cured by taking medications ordered by a doctor after proper diagnosis.