I have read your question,With out physical examination and medical history , it would not be suitable to come to any conclusion.
Red dots, itching and stinging sensation are generally symptoms of an allergy
, this could be due to anything ,some times medicines also cause allergy . So i Would suggest you to consult another physician an do mention your medical history before him.
If you have any further doubts feel free to email me .
I hope your mother gets well soon,