Dustin literally told Joe in his post-fight interview he was hurt so bad he couldn't see, but luckily Chandler was throwing looping shots instead of straight shots which would've taken him out.
Dustin was covering up completely blind and flailing his arms praying anything coming would be Chandler's trademark looping shots. Luckily for him, they were (and that Chandler eventually decided to go for a TD).
It was the same thing in Conor 2. Poirier again said he got hurt and "flashed", but that Conor never followed up on it to make it matter:
https://talksport.com/sport/mma/823102/ufc-257-highlights-dustin-poirier-conor-mcgregor-knock-out-score-cards-ufc-257/#:~:text=“He flashed me a couple,was going to pull away.
Poirier's chin has never improved. People just fight him really stupidly and so don't actually end up hitting him when he's hurt, and he's a much more seasoned veteran nowadays who can stay calm and maintain his defence around his opponent's tendencies even when he's hurt.