This poem could be improved by more attention to each couplet. First, decide upon some particular meter. Here is example:
Thoughts that were tame and quiet, (7 beats )
now unleashed wild and frantic! (7 beats)
Python desperation squeezes at the throat (11 beats)(Python squeezes at the throat)(7)
Heart pounding like a racehorse. (7)
Sweat forming perverse rivers seeking (9) (sweat forms, perverse rivers seek) (7)
every crevice of the body. (8) (out crevice of the body) (7)

Or, here would be another way to write it: (iambic pentameter)

"Tamed, quiet thought unleashed a frantic storm: (l0)
A python squeeze at throat means to do harm. (l0)
Racehorses plunge through rivers of my mind (10)
Body sweat streams rivulets by design. (10)