Just a few minor but significant notes.....
There are several types of "stim" units that fall into one of several classes: direct current units, which produce a net amperage transfer from one pad to the other over time and is capable of burning the skin. Aka iontophoresis. Then there is the balance of units being sine wave, square wave, gated sine wave, etc. that has no net charge exchange and cannot burn you. Can sure tick you off though if misapplied! TENS units have a very small net exchange and while conceivably could burn, never seen it happen. If it did, it would be more due to inadequate patient instruction or improper use.
Pad allergies make more sense or even dry or damaged pads. Newer ones like inferential, H-wave...somewhat variations of the same, to a degree.


When it comes to MRI's, you might be interested to know that there are studies out there that state that 60-70% of all abnormal MRI findings (disc and degeneration issues) are in ASYMPTOMATIC individuals! They have no pain.

There are good and bad people in everything.