Question Peach Airlines: Landing at Haneda and Staying Airside?

I'm currently on an NH International flight heading to HND, with a Peach Airlines onward flight to ICN. I just realized I might be in a bit of a pickle. I can't check in online, and the app isn't an option since I can't download it mid-air. Does anyone know if it's possible to stay airside at Haneda and make my way to the Peach Airlines gate without going through immigration? Any advice or similar experiences would be a huge help right now!