Help! Wiped cam lobes? - Video inside

With the intake valve open on that cylinder, the exhaust valve is on the heel of the lobe. If there is not a lot of slop and play on that rocker, then the hydraulic plunger in the lifter has taken up all the slack or all that it can. If the rocker is in fact not opening and closing as much as the others and that looks to be the case by your videos, your going to have to pull the intake so you can inspect that lobe. You may find others with some wear on them also. That lifter is more than likely mushroom and will be a PITA to remove. A faulty lifter will not necessarily damage the cam.