Yeah, add lye. Try to estimate the amount of additional water got mixed in and add NaOH accordingly.
I'd also like to say that from my experience, the heating is not really necessary. If you use enough lye you will rarely have an emulsion(if that was the reason heat was used). and if you do end up with a bubbly emulsion you can just have a sink filled half full with hot water and just sit the jar down in there for a little bit and it will settle.
They say that gentle heat will help push the dmt into the water. But IMO if you really want to add heat to the mixture you can just put the bark in the water/lye while it is still warm(not super hot though) and it will help push some of the dmt out of the bark and into the water. But to be honest i've had more problems from adding heat than i've had benefits.
Don't take this as gospel, but have your friend do a heated one and one without adding additional heat side by side and compare the results. If he does it, share the results!
Just a thought! I hate to hear about people having problems like this when they could have been avoided!
Good luck!
Coinci-Transcendentalism