What Causes Bald Spot Above Upper Lips After Shaving?

Hi, I recently noticed a bald patch after shaving on my moustache. I am thinking I may have damaged the follicles when I switched to the side trimmer on my electric razor to reach a hair the regular foil couldn't reach. It's been over a week and the bald patch shows no growth. What can I do?? I have a feeling I pressed too hard and too many times on the affected area.