Could you explain in more detail what happened and where and how you are stuck.
How excactly did you get softlock?
And what did you do to make it happen?
If you should be completly stuck without backup, I can offer to fix your save file.
In the sunken ruins I pick up the music box and got the mermaid tf I also had picked up the deep sea pearl earlier so there was a sparkle and I interacted with it and got the sea monster tf, I was then teleported back up the the first room so I went back down the stairs having not completed the mermaid quest the stairs back up was blocked and I could not use the dive ability that the mermaid form has so I was unable to reinter the water. (Note: I save every time I come across a save point so I have a save that I can go back to, thanks any way.)