I did a 7 day fast over a decade ago to get rid of my acne. It got worse for a few days but 2 weeks after my fast my skin was totally clear.
The term people use is healing crisis so that might be what’s going on with you.
It may be a “gets worse before it gets better” situation as mentioned in other answers. Continue to use the Cetaphil. It’s got nothing but love for your skin. If the condition worsens or just sticks around, see your dermatologist. It could be totally unrelated and sounds like how my psoriasis came on. Could also be eczema. Or even a rosacea flare up, although if that’s it, it might be the first scenario. Fasting and going zero carb cleared my rosacea completely eventually. The point is, many people often associate a new or returning condition with a new diet but remember, “correlation does not equal causation”- a credo that winds up being true more often than it’s not. Other things you might not have considered have changed- weather and wind, your stress levels (which cause psoriatic, eczema and rosacea flares), whether your heater/air con vents need to be cleaned, etc.
when i first did a 3 week fast (my first fast beyond 24 hrs), my skin broke out in little acne bumps during the first week. none of my future extended fasts have produced acne since. i wonder if its just a first-time reaction to fasting? interesting how this happens to people.