Car: 1992 190E 2.3 8V

The car had a bad head gasket (oil in coolant, major oil external oil leaks) so I replaced it. The head was decked 0.005" and it had to be welded in cylinder 4 because it was damaged (didn't notice the damage when I pulled it because of carbon buildup, the shop told me after they cleaned it). I re-installed the head, followed the instructions for torquing (the instructions for the gasket had a different sequence than the manual, I follower the gasket instructions) and I reset the tensioner (pulled the plunger, re-inserted it from behind until first click, then put the spring and cap back on.

I started the car yesterday, everything seemed fine. I went for a short drive, no leaks, everything good. I went for another longer drive this morning, got the engine to 90C, highway driving and all. Just when I was about to come home, the engine started ticking loudly. Kinda like a valve lifter tick, but it could have been an exhaust leak right at the ports too.

-Checked all the manifold studs, all good
-Found a vacuum leak, fixed it
-Spark plugs all tight
-Opened the valve cover, no visual defects
-Good oil pressure/oil level
-If I push down on the lifters, they are all tight (would a stuck lifter be loose?)
-Timing was good when I put the head back on. I figured since it ran fine this morning it was ok. Could it have skipped a tooth even after driving for a while with the tensioner good?

I need the car by tomorrow, its 4:15 PM and I'm panicked.