From what I've heard, according to most people on here just leave it alone, and it should be okay. I'm kind of a newbie though so take my word with a grain of salt. But I've seen a couple of posts that mentioned leaving it alone. I have a fatalii or Caribbean red that is doing the same thing.

I would give it a couple days. If it doesn't pop, then you might want to try to help it out a bit. Maybe put a "drop" of water on it every few hours and see if that doesn't soften up the shell.

I might suggest that you plant 2-3 seeds per container in the future. That way you are almost ensured one will come out nice and strong. Just snip the two less vigorous ones after a while and let the strongest one go. This is what I do unless I am really hurting for seeds.
Bruce

I'm getting a lot of helmet-head disease. 5 (6?) cases so far out of about 80 sprouts. I have tried my best micro-surgical techniques, but these little guys are so fragile the slightest tug will uproot them, so I let them die in peace now. Besides, I need the cells.