I'm a first year beek, and started my bees on foundationless frames. We have had a heck of a lot of rain and cold and I didn't look in on my bees too often the first few weeks, and they built some wonky comb. I did a lot of studying on YouTube University and in Blogland and learned a few techniques for fixing comb that have helped a lot.
If a comb was seriously bowed out from the frame, I cut it off at the top (a nice serrated bread knife worked well) from the top bar, straightened it out, then clipped the comb with a hair clip like this from the Dollar Store:
Make sure you get hair clips that have openings on the top so you can use tie wraps to connect it to the top bar. The bees will build wax around it.
There's a transparent and a brown hair clip on this frame.
When I found double layers of comb or comb I couldn't get back into place, I cut it out and used rubber bands vertically and horizontally to make a cage for it. The bees attached those pieces to the frame and built it out pretty well. It feels drastic to do this 'surgery', but after they start building straight comb, they seem to keep it up. And while this comb won't win any beauty contest, the ones built next to it were straight and neat, and that's what's important.