Vivid Dreams after Acupuncture

Not knowing the details of your case or the treatment points used, what I can offer should be taken lightly. There is a clinical significance to dreaming in Chinese Medicine and specific pathologies for nightmares and other patterns of dream activity. Generally dream disturbed sleep falls into the category of heart blood and/or yin deficiency - which is often a strong component of anxiety/PTSD, etc. - in addition to the LV Qi stagnation which is often involved but not necessarily.

There are a range of responses to acupuncture and side effects are generally very, very minimal - if any at all. From a very basic perspective an increase in dream activity could be contributed to by the acupuncture by focusing too much on movement of stagnation instead of building up a deficiency of say Heart Blood.

What you are describing, however, is something more akin to building your perception abilities. Certain people experience a range of perceptive changes like this over time and anything from acupuncture, yoga, tai chi, meditation, etc. can start and/or contribute to this process. It's possible that the acupuncture is contributing to some "ability" you may have already had innately.