Bent a chain link back into alignment. Will it hold? Yesterday, my chain dropped off the chainring and one of the links got bent sideways (didn't take a picture). This caused the chain to skip whenever this link would go over the casette.

I used pliers to bend it back into alignment. It's not skipping anymore, but I'm wondering if the chain link is compromised now and will fail under load (e.g. on an uphill, probably in the worst possible spot to get stranded).

I don't currently have a chain tool - should I buy one and remove the affected link? Should I replace the chain altogether (it's still new, only got ~600 km on it)? Or should I just keep riding?

Picture of the affected link after I've bent it back:
Your chain is very likely weakened because the joints between the outer plates and pins will have been deformed. Yes it will fail when you are applying maximum torque, likely when you are goin uphill. The problem isn't so much being stranded, it's the nasty crash you'll have when that happens.

You can't just remove an inner and outer link because the chain will then be too short. If you previously replaced the chain and have a few spare links after you cut it down you could splice in a few links.

Personally, I'd just replace the chain.