Welcome to justanswer.
I am aware that you have had to wait for long time to get an answer.My apology for that.
She can take an anti allergic tablet like cetrizine which is available over the counter.
She may also use an anti allergic medicine like benadryl
But if she develops trouble in breathing or excessive facial swelling you need to get her to ER.
You may ask if you have any questions till you feel satisfied.