You need to chill out. First of all you are 22. *** Is extremely rare to begin with and the likelyhood of you having it at that age probably goes from 1/100,000 to 1/250,000. Not saying it's not possible but I believe we all have a 1/75,000 chance of getting struck by lighting to put it in perspective.
I have twitching everywhere, slurred speech, dull back ache, muscle cramps as well and my neuro has given me clean bill of Health as has yours, but I still doubt him every second of every day because I have HA. Same like you he only did a physical check no eeg. But we need to believe them. Have they been wrong, sure, but if they were wrong often they wouldn't be neuro's, trust me on that.
i would suggest therapy if you aren't already in it with a clinical or psychologist who can help. Has been successful for me in the past, but came back at me this time extra strong because I let my guard down. Stay on your meds and keep occupied. Try yoga or cross fit get the endorphins moving.. Don't worry about *** unless you have clinical weakness somewhere and even then still it's a possibility you wouldn't have it. They do say *** can possibly happen after a major surgery or injury, but it doesn't seem like you have had either of those. Your age for me is the caveat. If you were my age 43, then you might need to get a closer look. Even still so rare. I'd love to be 22 again. Enjoy yourself and stop worrying about disease. You can't do anything about it. Stay healthy and active and the rest will fall into place. I was you 21 years ago and I'm still here. Barely, but Im still here. Lol.
The twitches are so annoying but as your anxiety increase so will your twitching. Whatever you have to do to relax, do it. You will see the twitching subside.