Mefenamic acid allergic reaction?

Ive been prescribed mefenamic acid for 500mg 3 times daily for my nerve pains after having shingles.

I wad also given magnesium trisil to accompany the above medication.

However, after taking the 1st dosage at 11am, i start to have puffy eyes so i think i may have allergic reactions. should i continue on the medication or stop taking them? I cant contact the clinic now because its closed due to the coming holiday.