Just some general comments:
-You should probably leave the page size larger. The raw was 1536 height, and I'd recommend leaving it at that. This raw doesn't require much leveling, so it doesn't become too sharp or anything.
-There's excess space on the bottom and right sides that should be cropped off.
-About the changing to "OK!" thing, normally you'd consult the translator, and if they think it's fine (which it probably is in this case) then that's all good. In a case where you can't change the text to be smaller, sometimes you can increase the bubble size by copying a part of it and moving it over, then using the clone stamp or brush tools to fill in the gaps in between. Just make sure no important art is being covered up when doing this though.
-On the first challenge you did, I could see some filters were used. I don't know if they were used here or not also since the page is small, but they aren't necessary for this kind of raw.
-Could probably put a line break after the "Gentle," in the "Gentle, dude, gentle!! I'm delicate!!" bubble.
Anyways it's pretty good overall.