I gotta say, as a gay man, I'm so tired of Asian BLs going the "butt pain" route after anal sex. I guess women writers think it's somehow cute but, in order for a guy to be so sore that he can barely walk or sit down, he would have had to been brutally raped with no lubricant. It's not realistic at all, even for those into BDSM.
Let's not worry about that too much. Many viewers (including me) never rate a series until it's completed. Unless the series ends up really disappointing in the second half (which I doubt), it will go up.
I can't stand Earn and Kaew. I've already decided that their annoying presence will bring down my rating one full point from what it would have been otherwise, after the series has finished.