Don't fret. All of us have done some regrettable things with fabric and learned the hard way. Somehow it seems a lot is on something we wish it hadn't happened such as a project from the previous generation.
I wonder if that will be flat when you put the rest of it together. There are so many bias edges in a Lone Star that it may simply be that causing your issues. You can work a lot of that in with some determination and patience. Most quilters are well acquainted with the "fudge factor".