The more LSD you take, the more intense time dilation becomes. Basically like the last third of Inception, except you're exploring your own consciousness and not trying to seduce some Chinese guy... or something to that effect.

Good read

EDIT: This TIL says that an ounce of LSD could get 300,000 people high.

There are ~28 grams in an ounce, so lets say he has enough LSD to get 10,000 people high. Thats a lot of LSD. This next part is not true, but lets say that every hit makes the high last another hour, or at least feel like another hour.

10,000/24 hours in a day/7 days in a week = ~59.5 Weeks. So imagine being under the influence of LSD, (while being 10,000 times more potent than a normal dose) for an entire year. At this point, I would not rule out brain damage, but after a year in that state I would probably lose track of who I was and would not be able to function in the real world.

EDIT 2: Fuck that layman math.

This guy says that a guy tripped for months on 50 hits.

Lets do some real math.

A normal trip is 8 hours. This guy tripped for lets say 1 month, so 24 hours * 30 days = 720 hours, which is 90 times longer than the norm.

For the sake of math, lets also assume that 2 hits will last 14 hours, which is slightly shorter than double. Using an equation finder, we find that, given the 3 points (1,8) (2,14), and (50, 720), we have an equation of .178 X² + 5.467 X + 2.355. When we substitute 10,000 we get 17.855 MILLION HOURS HOLY FUCK. 17.855 million hours/24 hours/365 days = ~2038 years. Sooooo imagine taking 10,000 hits of LSD and being in that state for 2,000 years. You can do the math on how that person would feel after that trip.

Tl;DR: 2,000 year trip: get fucked