Hi Penny Lane:
Baclofen gave me back a quality of life I thought I would never have again.
It does not work for everyone, but for many who have spasticity it is an effective drug.
You are starting on a small dose - 15 mg. You may be titrated up, since you can take up to 80 mg/day.
It's hard not to overdo it when you feel good. Baclofen, when it works, tends to make the pain go away for a while and it's easy to think you are 'better'.
I started on 15 mg. and now, a year later take 60 mg/day. It makes me sleepy and I have days when I have to nap, but it is wonderful to be able to get out and about.
No liver problems yet, no side effects other than drowsiness which was worse during the first month and for a week or so when I increase the dose.
You will notice when it starts to wear off. I usually look forward to taking my morning dose. It takes about an hour and a bit to start working, then I can be heck on wheels.

I still use my cane and weakness is only an occasional problem.
Good luck - let us know how it works for you.