Book Wurmple

Oshawott sidequest error. Please fix. Thanks Game.rxdata

I'm playing V10 and I'm stuck in the West Gearen Sewers because I'm unable to beat the Dimensional Garbodor. My team gets destroyed, especially because my only Ground-type is a Gastrodon with Mud Bomb which gets rekt by Giga Drain. I caught a Nidorino at Valor Mountain but it's not in my current team. I want to withdraw it and grind it up but I can't access a PC because I can't leave the north of West Gearen city and the gym is locked. Any suggestions? I could simply grind up my team to level 60 cap, but that would make all the plot events leading up to the gym battle a waste of time. My team is level 56, with Infernape at level 58 and a filler Drampa at 46.

Thanks, I was looking around Texen's gym at the very top.

How do I get back to Carotos Mountain after starting V9. I want to go back to the Corrupted Cave and catch a Sandile. Sheridan Village has changed so I can't access through under the waterfall.

I've caught 7 Horsea using a Compound Eyes Dustox in Ametrine Mountain 2F, none of them carried a Dragon Scale. This thread: said that they carry Dragon Scales at a rate of 5%, with Compound Eyes boosting that to 20%. Has the hold item been removed from the game since 2014, or should I keep trying to catch Horsea in hope of getting a Kingdra?