It's likely that it wasn't completely smooth to begin with and just became more noticeable as it dried.
I also use tylose, and even when I think I've put in too much I can still get it to dry crack-free by doing 2 things that never fail me...
1. I ALWAYS microwave the piece I'm working on...usually it's not more than 10 seconds since I literally warm each piece separately (leg, other leg, arm, other arm, etc.)
2. After warming, I ALWAYS firmly roll the fondant (no matter how small) into a very smooth ball...only then do I proceed with trying to shape it into something.
When I'm using templates (converse sneakers) and the fondant/tylose has to be rolled out instead of modeled, I still start from a smooth ball.