Is $800 to fix vinyl pool liner pulling out of place a fair price?

I've spent all this time getting my pool into shape, and I noticed that the vinyl liner seems to be pulling down from where it's supposed to be a bit. This is happening in about 4 places (this is the worst one). I'm wondering if it's worth it to do it, and if my liner will be damaged if I don't fix it. I'm also looking into ways to do it myself, but I got confused with people using hairdryers and spatulas on YouTube. I don't want to rip the liner or electrocute myself. The liner isn't that old (less than 2 years), so I don't think I need to replace it. I like the liner lock idea and will probably do that for the rest of the liner to prevent future issues. I'm not sure I'll be able to get the liner back in place in the areas where it's not in the track, as it doesn't seem to want to go back if I just try to pull up on it. I've tried to pull it back up, but it did not cooperate. I just have to figure out how to get those areas back in the track first.