Hm.. maybe the top layer would be dry enough.. can you wring it out with water dripping from it, or is it not that wet? You could gradually put it in I guess; too bad your snake is not in shed mode; that would be a bonus: added humidity!
If it were a covered tub or something, I would def. advise not to put it in yet, as the humidity would skyrocket.. but it usually just dissipates through the screen lid.