It's shonen manga. Being upset about a manga is the most stupidest thing do. It's not like i particularly tried to conserve something in my memory. I just happen to have great memory since my youth allowing me to remember a lot of things i don't particularly try to pay attention of and the moment you quoted me i remembered your username and your thoughts from last chapter, that's all
He fixed nothing. He only used his strings to stop himself from dying but the damages were already there. Both Luffy and Doflamingo acknowledged that, with Luffy even admitting that he'd not let Law's attack go to waste. He is weakened. Before gamma knife, Luffy couldn't land a single hit. After gamma knife, base Luffy outmaneuvered him at one point. The difference is blatantly clear
Not showing something doesn't mean he can't do it anymore. Doflamingo, used his fingers to fight Luffy last chapter, and last time I checked his fingers weren't damaged and there is no reason his ability to use his fingers is crippled, so he used his strongest power at its full strenght.
His flying ability is to hang himself from clouds like a puppet and fly around by controlling those strings, so unless his ability to think has been weakened or his string ability has been weakened by the damage then that wouldn't be weakened.
He was shown to be capable of physically fighting still so clearly he can still use his physical attacks so he can still fully function.
And if we are using biology we can factor in adrenaline which would erase the pain from the organ damage as people have a tendency when in the fight or flight state to completely ignore pain. People will walk around with broken bones and not even realize it until the rush wears off.
And if his organs were in as rough a state as you claim then shouldn't he be constantly coughing up blood from the internal bleeding, but he stopped after he fixed his organs so clearly they are being held together just fine.
Doflamingo was able to take Luffy's punches pre-gear 4 but after that, it only took 4 blows to leave him a single blow away from death.
So really Doflamingo's injuries are a moot point, he has plenty of ways of fighting without letting his injuries bother him and they are in the air which gives him the advantage anyway.
And clearly Luffy completely over powered him in the fight, so even if he wasn't injured Luffy would simply need to hit him more times.
So long story short, if Luffy simply needs to extend the time limit on Gear 4.