Could use of TENS machine have caused pain?

[RedskyThisNight]

As per title really. DD suffers from unexplained chronic pain in her foot. Has been recommended to try a TENS machine to see if it helps. On the first day it really helped - great! On the second day, it didn't seem to do much, DD ended up moving the pads around a lot and turning it up more than day 1. Five hours after she'd stopped using it she had severe pain in her foot which was worse and "different" (in a way she couldn't explain) to usual. She's now scared to use the TENS machine again but I'm not sure that was really the cause (why would it take so long for pain to kick in?). Any knowledge or experiences?

If she has CRPS (a common unexplained pain syndrome that is caused by non pain signals getting interpreted by the brain as pain), then TENS does mess with it as the pain pathways get even more confused. When I tried it I would get weird pain echoes and increased pain afterwards.

Thanks for the response- that's interesting. CRPS was mentioned as a possibility at one point, but then got ruled out as she didn't really have other "standard" symptoms. However, there does seem to be general (medical) agreement that for her, non-pain signals are interpreted as pain, so I guess she may have experienced something similar to yourself.

I don’t find that with me although in certain places the zapping can affect the muscles as they are forced to contract over and over in a way you wouldn’t normally. When I use for migraine pain I have one on back of my neck and next day muscles are sore because they have had good work out. Or like PP said it does depend on the cause and often hard to tell.