Good job on the upcoming 90 days.
Everyone's brain/nervous system is different. In some folks, residual tremor can hang around for a long time. I had it for a lot longer than 90 days, but it did eventually go away. Well, 98% of it, anyway.
The danger, for me anyway, was that I'd get frustrated. I'd put together a sober run of several weeks or even several months, and then my despair that the tremors or other lingering symptoms would never go away would give me an excuse to drink again.
I did this in the full knowledge that I was only compounding the problem by giving in, but that's addiction for you.
Hang in there, and your tremors are almost sure to get better on their own as long as you stay sober.
The only exception would be if you have a non-alcohol-related condition which, as other posters have noted, should be diagnosed and treated by a physician. It never hurts to rule out the possibility.