Responses
I went back to compare, I think the art style is the same but they gave Dohu the eye bags that he has currently that he didn't have back then which makes him look so odd in the flashback. That's just my opinion.
I totally get what you mean about the eye bags, but in my opinion, that's exactly why the style did change, putting his current eye bags on his past self is exactly what ruined it! It completely destroyed his cute little sea-urchin vibe as well as that distinct, softer style the older chapters had (￣∇￣")
for those who say the artstyle hasn't changed much, y'all are blind af, cuz the dohu in flashback was not my lil sea-urchin thingy ╥﹏╥