Is there anything I shouldn't do after?
Basically, no... though it is good to avoid alcohol.
You will most likely find your own balance with this: some people feel it is better not to use the gym after treatment, schedule an appointment of a comparable nature (e.g. a massage), and avoid things like a sauna or swimming.
None of these things will cancel out the effects of the treatment, as this reaches beyond the first few hours. So if you do like to go to the gym after a treatment, for example, try it and see how you get on.