Translated for fun using online translation resources, I don't speak Japanese so I used a mix of Chinese/Japanese/context clues. Hope you enjoy

Thanks for translating this. Unfortunately you fell for the newbie trap and used the 1280x resolution resample pages for editing instead of the original raw which is around ~2221 x 3107. For gallery viewing, e-hentai downsamples all images to 1280x resolution so if you downloaded the pages without using the original source link, you got the reduced version instead.

Another possibility is that you downloaded the raw from one of the aggregator sites such as NH. These sites only copy galleries from e-hentai at resample quality and thus don't have the original resolution versions available. You shouldn't use these sites as a source for your raws.

Always check that you're using the original raw before you start editing. If you ever see the resolution being 1280x something, then most of the time that means something is wrong and you got the wrong version.

Here's some ways you can download the original full resolution version of any gallery on e-hentai:
1) Torrent download if a torrent is available. Avoid any torrents labeled 1280x though.
2) Click on Archive download and then Download Original Archive.
3) If you prefer to download one page at a time, make sure you download using the Download Original Source link located below each opened image in the gallery.

Base +34, qwersad222 +18, Walker009 +9, FertyJukli -10, MSTallgeese +6, nsed +6, xxSidoxx +6, Unwashed +6, occo +7, White Joker +25, Benny-boy +29, ilwaz +19, awadsss +5, and 9 more...

Raw can be found here: https://e-hentai.org/g/1882868/0b968d4a42/
Chinese TR: https://e-hentai.org/g/1887356/ca280397be/

Thanks for this upload, although I advise you to learn Japanese if you want to translate Japanese doujins

Base +47, PanstLove +6, White Joker +25, Darthnader18 -7, awadsss +5, sleazeball -4, sharks5000 +7, IncognitoMaud -6, oliver82 +6

Wait for better translation. This one sucks in all departments lads.

Base +16, MSTallgeese +6, MrPonty +6, occo -7, fagduha7brry +3, White Joker +25, ncc1701z +18, Darthnader18 -7, awadsss +5, HeavHo +13, Shota_Cried_WolfGirl +6, highnass +6, Boomer30569 +7, and 5 more...

Sometimes you wrote little brother, sometimes older brother....
Just wtf, don't you find it weird that it makes you want to re-check the raw materials?
I just took a glimpse of the JP one and it's all "oniichan"

Also I'm was checking this panel that said "But wearing my little sister's clothes feels so good" to check whether the little sister part is correct, but turned the whole sentence is different.
*original sentence is「じ 自分の女装姿オカズにするなんて」
I'm not that good at putting this into sentence myself, but the actual sentence should mean that find it's unbelievable for him that he's using his crossdressing self (from the mirror reflection) as a fapping material.

Based on that mistake, I try to find out more. There are many inaccurate things, but kinda forgivable since it's still within the context, I'm not that picky.
But something like this is really made me go facepalm.
「お願い 治まって 俺のおちんちんっ」 should be "please.... calm down... my penis"
translated as "come on.... calm down... oh no... she's staring at it so intently!"
so I stopped reading here.

Base +6, ncc1701z +18, Darthnader18 -7, awadsss +5, RustySword7 -6, highnass +6, Boomer30569 +7, IncognitoMaud +6, LachesisLegion +4, Keltzar +7, Hyoros +14, cynamonbunz +34, tobeunforgiven2 +24, and 7 more...

Definitely messed up the little/older brother thing, might fix at some point.
Don't really feel bad about things like adding "she's staring at it so intently" though, this was something I did all by myself, for free, and it all still makes sense in context.

Base +5, awadsss -5, Shota_Cried_WolfGirl -6, HeavHo -13, Chileandude +6, Xalren525 -6, highnass -6, Boomer30569 -7, mars2 -8, Mr.Awesomeness -6, IncognitoMaud -6, astral02 -16, saastokoko -6, and 6 more...