Rosacea triggered after botox?

In the realm of anything can happen in medicine and that there is always a first time for everything, I suppose that perhaps the stress alone of receiving the Botox treatment might engender a flare of rosacea in someone who has the tendency for it. However, I have personally successfully used appropriate concentrations of Botox (and other neuromodulators, such as Dysport and Xeomin) to treat the persistent flush (redness, erythema) of rosacea and even the inflammation of psoriatic plaques. More likely other factors may have been responsible for the flare that you describe and this should be explored with your dermatologist.

Although rosacea is not a common side effect of Botox, it is a possibility you are experiencing a side effect from your treatment. Contact your dermatologist for assessment and appropriate treatment. If your symptoms are from Botox they will diminish in approx. 3 months.  

It is possible that the prep used to clean the skin prior to the injections flared your rosacea.  People with rosacea find they do best using mild products for cleaning and moisturizing their skin.  When prepping the skin for injections, stronger more irritating cleaners are used.