The symptoms as mentioned suggest that the red blotches around mouth were caused due to any particular food products.
being an Antihistamine preparation provides relief from allergic symptoms.
But it is always better to administer a medication as per advise of a Pediatrician...otherwise it may lead to side effects.
So...if such episodes occur repeatedly, then it will be better to consult a Pediatrician
& find out the exact cause of development of red blotches around mouth and lips.
Wishing your daughter a good health.
Thanks & take care.