Pop goes the...
Lex decided not to measure time and instead just focus on his search. Such a mentality, alongside the fact that it was perpetually sunny in the Midnight realm made it so he really could not tell how long it had taken him, eventually there came a time that he scanned the entirety of the region, but was unable to discover the resin or anything else that might hint at it.
That meant he would need to conduct the search underground - how wonderful. He did not need to think back to the time in the Crystal realm when he got buried underground, or the dragon's basement, or basically any time he went below the surface, to know that this would not be a pleasant experience.
If for no other reason than because he had no way to easily travel through solid ground, this was going to be a tedious journey.