It sounds like you inadvertently applied a legitimate growing technique called supercropping.
Maybe a little too early, but this may turn out to be a good thing.
If the top of the stem is simply bent over, and not completely detached from the rest of the plant, I'd recommend leaving it like that. Yes, there is a risk of infection at the point where the stem is bent, but just keep an eye on it until it heals up nicely. Put some fungicide on it if you think it's a real concern.
What's happening is that you're exposing more of the top section of the stem to light because it's now horizontal to the ground (roughly), which is a good thing as it will produce more buds at the node sites as it grows outward and upward.
And the section of stem below the bend is actually going to receive a little bit more of the nutrient uptake than it would have before the bend, because the flow of nutrients back and forth between the top section of the stem has been impaired... a little.
Hope this makes a little sense. I'll try to find some links to more details about this stuff when it's not 5am and I haven't been up all night and am not currently baked.