When he went for some time without actively using the Force, but instead simply kept it pent up
within, it burned. It was like having a big chunk of fire lodged behind his sternum. He found it
hard to breathe, harder to sit still. It quite literally raised his internal temperature; after a few days
Kaj found himself sweating and running a low-grade fever. If he kept it bottled down much longer
than that—say, another week or so...well, he'd only done that once. When he'd woken up in the
middle of the night, he'd felt at first blessed relief—followed by heart-stopping fear.
The bed of the cheap resiblock he'd rented for the night had been soaked with sweat, and in the far
wall a circle a meter wide had been charred into the paint.

Star Wars: Coruscant Nights III: Patterns of Force: Chapter 2