DHS H3 Provincial looks normal?

1: put too much booster and booster soaks the topsheet through the sponge

2: put booster on the topsheet

3: laying the rubber while boosting it on some surface that can be affected by booster thus ruining the topsheet (most likely)

We wouldnt know if its a knockoff unless we knew where it was purchased. 

I can see a few fingerprints (that's what they look like) in the picture. I am guessing you had some booster on your fingers when you touched the sheet, perhaps? Additionally, this kind of oxidation does happen if you leave your rubber in hot temperatures. It isn't uncommon for chinese topsheets to get oxidized this bad. What i would be surprised with, however, is it not getting back to normal after you place the protective plastic sheet back on top of it (after cleaning this sheet with water and soap obviously) for a few days (hours maybe, if you are too anxious).

Usually, when my chinese sheets get oxidized, it is because I did not have the plastic covering on top of them. It does come back to normal when I apply the protective cover back though.

Also, the booster has a different kind of effect on topsheet (if you apply it directly on it, that is). It just makes it swell up really weirdly and it looks way worse than what you have here.