Any tips on recovering from what I percieve as a bad chem mark and rank?
Yes it's very simple actually. Forget what happened, and start studying. Ask as many relevant questions as you can, do a fair amount of past papers and LOTS of questions.
When I was doing chem, I stuffed up one assignment that was worth about 30% or 40% can't exactly remember, and everyone happened to do extremely well. And then the inevitable happened, my rank dropped from 1st to 30 something. I started questioning my ability in chemistry and felt sorry for myself for a while. Then, I forgot about what happened, and decided to give it my all anyway, I studied very hard for the trials and honestly really enjoyed the process, The trials happened to be quite difficult that year, so the majority of the students didn't perform as well as expected, and luckily I managed to get a 95. I was ranked equal first for the trials and equal second overall.
Moral of the story: you can boost your rank, just figure out what went wrong and make sure it doesn't happen again. Even if the damage is too much to be fixed, the best thing to do is to move forward, regardless of whats possible or not. All the best!