Hi Hana-I remember you from the infant sleep boards
How long will he cry while lying down? Is it a mantra cry (just settling) or does he seem in distress? I would think that even if it's dark, he'll know you're there. If you want to be sure, come up with a reassuring phrase to repeat that will calm/soothe him. "You have your blankie, your teddy and it's sleep time now" As long as you're in the room it is not any form of CC or CIO.
How is your lo with teething? could there be molars working their way through?
Lastly, post your typical routine...as that will help people see if there could be something else out of whack.
Good Luck. I'm still struggling with Cole's sleep, so likely not the best to advise