Relliah

Hello, I am pretty new to Rejuvination. I had just caught a lucky break in defeating Marianette at the mansion, and I arrived in a place at the sewers but, just my luck, I could not escape and my poor Lycanroc was defeated (It was on red health and my only non-fainted mon), so I had returned to the manor after blacking out and now I'm completely lost. I feel like I am stuck, and I tried going to route 3 but Venam did not show up. Is there anything I can do or do I have to make a new game?