The Boston Scientific trial I had was completed with the working unit mounted at my waist in a velcro fastened cloth wtih a pouch for the device. I did not experience burning, and the unit did not touch my skin directly.

When I recharge my permanent unit, I do experience a feeling of warmth at the contact point where I mount the recharger over the internal working device. No discomfort is associated with the recharge endeavor, though.

I reckon you will need to ask doc or your rep,
Mark56