I used my mat the last two days for two sessions yesterday at 50 degrees but I’m having a sensation of dry mouth that won’t go away and some twitching. I do have Lyme disease.

Sorry that I cannot give any medical advice here; you should consult with your health professional, as always, when you notice any adverse symptoms.

A dry mouth is the first symptom of dehydration. It may be generally dangerous for the body. 

You should always drink A LOT before the procedure, during the procedure, and after the procedure — if you feel dry mouth, there is not enough water in the body.

And it should not be just water; you may need to replenish some electrolytes and minerals as Ca, K, Mg, Na, so some fruit juices and mineral water rich in K and Mg would be better.

Twitching may be a sign of these salts’ serious deficit or imbalance. You may have overused the mat and need some rest, in which case you should not resume use of the mat without your doctor's approval. 

At least not unless you limit your use to the generally safe, lower temperature settings of 30-35°C. Take care and use common sense, and everything will be fine.

The mats are really powerful, and many customers never use them on high heat. 

We always recommend starting with the lowest settings and short sessions and watch how your body reacts. You should also have some rest between the procedures and never start with more than 3 a week before you are better informed about how they influence you.

What is not enough for one customer may be too much for another because of differences in age, weight, and body composition.

Many folks with Lyme use the mats on higher settings and have benefits, but it is very individual — so listen to your body and your doctor and adjust settings accordingly.

In general, watch for the signals of overheating — dehydration is one of them — limit your session time and use the mat only on the lowest temperature settings.