It can be Urticaria
so important thing is dont give any spicy food, junk food like choclates, icecream, pizza, cheese and all fried food.
Ask her to drink enough water. Give her healthy vegetarian diet.
and give following medicines for 1month-
1- Mahamanjisthadi kasayam 3tsf mixed with 5tsf water after food twice daily.
2-Tab Neem 2tab twice after food.
2tab bed time with warm water.
4-Tab Liv522tab twice after food.
after that let me know how she is feeling.