I mixed tylose with MMF and it was working great, but the flowers were not drying as hard as I wanted. So, I added more tylose I think I added too much, because now it is hard as a rock (after resting and coming to room temp). It is a bit harder than store bought GP at room temp.
I can work with it fine, after microwaving for a few seconds, but it is really rubbery and makes an already tedious process (carnations) even more tedious and hard to ruffle. I tried to heat it a little and knead in some shortening and a tad more water, but it's not really 'loosening' up.
Try kneading in a bit more fondant (no additional tylose)
Another option would be to add just a bit of egg white. OR a bit of shortening.
Depending on the recipe of the GP that you used, nuking it may have cooked it--that will make it unsalvageable. Too much crisco also ruins it.
I think adding some plain fondant to it is your best bet, a bit at a time, until you get the texture that you need--or pitch the hard stuff & start over.
Throw it away, if you heated it it just makes it set up harder.