There should be an update for the Horror Elements Mod to fix the lag when you look at the Herobrine Head! I had the same issue about a month ago but it should have been fixed since :)
Tip : Cave dweller now stalks you. His position can be spotted by the frequent cave sounds, which the closer the dweller are, the more frequent the cave noises emitted
I discovered the channel not long ago but I'm already obsessed, you two are so fun and the videos are so good that I stay up late watching all the videos lol you guys are definitely the best in this type of content