Tender skin on one side of face

For a week or so, the skin on the left side of my face + left and middle side of my scalp was very tender to the touch. It hurt, nothing too bad, mainly just a nuisance.

It stopped hurting, but now, a few weeks later, the same is happening to the right side of my face. It has been like this for three or four days. There is nothing visual to be seen on my skin, it just feels tender and even more so when I touch it.

For context, I have rosacea and I've been treating an outbreak for the last three months using Rozex (metrodinazole), Soolantra (ivermectin), oral antibiotics and recently also Finacea (azealic acid). I also recently started using a near infrared light panel that I now use 15 minutes a day. My face cleared up just before the first tenderness manifested. I don't believe the rosacea or the treatment to be the cause myself, but maybe? I just find it strange that it manifests on one side of the face at a time, when rosacea has affected my entire face and I also apply the treatments to all of my face.

I spoke to a medical professional on the phone who suggested I was about to get shingles, but that never developed.

Any ideas of what's going on?