Missed nepmas upload but here's one in time for the nep year. I messed with the contrast levels. I hope it looks better. Please let me know if you find a mistake. (Especially if you can make sense of the blowjob slurring because I literally stuck fingers in my mouth and I still have almost no clue what they're saying...)
Edit: Forgot the back cover. Also thank you for the advice and links @THDragon, I'll use them next time.
@tabibit0 While you did adjust the contrast, your scans aren't fully leveled. The borders are supposed to be completely black, but they still look splotchy. That's because your files are in RGB color instead of greyscale. RGB color and Greyscale have 2 different leveling histograms, but RGB color is pointless on files that are black and white anyway. To convert from RGB color to Greyscale (assuming you're using Photoshop), on the top menu, go to "Image", then "Mode", and finally select "Greyscale". Discard the color data, and you're done. But you still need to level your pages, moreso than you did before.
I'll level one of the pages so you can see how it supposed to look, page 4: /img/e-hentai/H2zSQ/1cd3c53066.png
Notice how the black borders separating the panels are fully black (without over-darkening the greys), as well as the "Dooon!!" SFX in the lower left panel. As a general guideline, if your initial scans look hazy and overbright, you need to level your scans. If your text boxes and bubbles aren't fully white, you need to level your scans. And if your borders aren't fully black, you need to level your scans.
This guide will show you how to properly level scans: http://viid.me/9Mez8
Hopefully this will be of help to you, and I hope you apply this to your future works.