Hi,
I had gamma knife five months ago and have developed hemifacial spasms also. I had twitches beneath my eye and tingling in my lips for about six months before the GK. The lip tingling disappeared for a while after the GK, but about two months ago I started getting more obvious twitching under my eye, and then full-fledged hemifacial spasms, that caused my eye on the AN side to totally close and my mouth to draw up. It lasts for about a minute and is very disconcerting. I worry they will happen while I am driving.
For about a week or two they were coming more frequently from every couple of days to every day and then several times a day. I have found that they are worse if I am fatigued or upset or even if I make certain facial expressions. I haven't had them in a few days and I am hoping they will go away, sooner rather than later. My doctor said it would probably go away after about a year and that I could take medications to control the spasms or else botox injections, but I am not interested in either unless it gets worse.
A number of people on the forum also seem to have had facial spasms. At first I was pretty unhappy about it. I figured, I have dealt as well as I can with the SSD, and I am working hard on vestibular therapy for disequilibrium issues, and I have headaches and intermittent ear pain and tinnitus that I do my best to either ignore or amuse myself by listening to the strange noises, and now I have facial spasms too! (Although I don't usually have all of the symptoms at the same time.) I am not sure if I would have developed them from the AN anyhow, or if it is a response to the radiation and/or possible swelling of the tumor. I have my six-month MRI coming up in about three weeks so perhaps that will reveal something.
So, your episode seems pretty similar to what I have experienced, and also to experiences other people have shared on the forum. I think some people have chosen to take the medications, with varying results. It's good you have called your doctor; please report back on what he says. My guess is it's just another variation on the overall AN experience that some people get and some don't. Good luck; I hope they go away soon.