Let's say I have a character with a +2 Consequence and somebody rolls +1 on their Lore check to cure it.
Obviously they failed their check, but is anyone else allowed to try? I can imagine that this might be best handled by just using Teamwork in the first place, but can one failure foul it up to the point where another person can no longer heal, or does everybody get a shot?
Should there be some penalty for a failure of 3 or greater to heal?
Recovering from a consequence usually has no penalty for failure. It's an overcome action, and failure at an overcome doesn't come with a penalty. If something was opposing you somehow, though, they'd succeed, which would probably be bad.
As for whether you can attempt recovery multiple times, the rules are silent. They won't provide an answer to this, because you need to look at the narrative for your answer.
In your scenario, it's naturally not going to be as simple as just a Consequence and a Lore check: someone has a wound, and someone else is performing surgery. Someone has their confidence eroded or they're intimidated or horrified, and someone's giving them a pep talk to snap them out of it. Someone is totally hyped up, and another person's trying to get them to calm down.
So when you're dealing with this circumstance, derive your answer from the narrative:
If you can say that yes, this second attempt to aid in recovery will be legitimate in this narrative, then go for it. Otherwise, probably don't make another attempt.
After all, by the Fate rules, we could all just roll our Overcome attempts several times until we get a good result, but narratively that wouldn't necessarily make any sense at all, and probably isn't good for the drama that makes Fate so fun.
If the PCs want to enable this second recovery attempt but the narrative's presently not allowing for it, they can use Create Advantage to change the context so there is justification to try again: find some Fresh tools, fish out A good book or A gameboy, summon up The iron will of a drill sergeant, or so on. You'll simultaneously get free invokes to pass to te roller so they're more likely to succeed.
I can see two specific ways others can sensibly try to help, that is within the spirit of Fate rules.
First one is pushing the original attempt along by invoking additional aspects that help.
Adrian has a broken femur (as a severe consequence) and Bart is trying to help him get better with his Lore skill trying to set the bone. Unfortunately the falls short of the target by 1. Chloe, as a survival expert, invokes it with a fate point and narrates that she took over to properly finish what Bart started.
The other method is trying another approach which can literally be another approach in FAE or just another skill in Fate Core.
Paxton is shaken (a mild consequence) from all the blood and gore he had to witness in the previous scene. Quincy tries to get him straight by talking it out with the Rapport skill, which doesn't really help. Riley steps in, and using her Leadership skill, she manages to get Paxton going, by giving him clear instructions about what to do next. We cross out shaken from Paxton's consequences because though he is still narratively shaken, it no longer affects him negatively, thanks to Riley's instructions.
Still yet, if the circumstances allow it, the original failing roll can also be taken as "success at a cost" as well. The cost may well be the time and resources of another character.
