[Legen...dary!]

So I've recently reconnected with some old friends that I haven't seen in almost 9 months. They invited me over to their house to chill last Friday and preempted them with a party that I had already said I was gonna go to, but that I'd "For sure come over next week"
So I was looking forward to chilling with them this Friday but I just got a text inviting me to a free acid party at another friend's place.
I really really want to go to the party cause I haven't tripped in almost a year and Idk when I'll see Lucy again. But I had promised them I'd chill with them.

LSD is a very important aspect of my life. But so are my friends, and I don't want to a drug to preempt my relationship with them.

What should I do?

The place where the party is happening is mad close to where they live, so I could leave early, but I think that would be even shittier.