Unwanted theme changes transferred to new theme

I made the huge mistake of making changes to my parent theme when I thought I was changing the child theme and now I’m not sure where these changes are (that was a few months ago that I was messing around with everything). The problems could be with things I just don’t know how to change, instead of with the changes that I made, so I switched themes with the hopes of getting things back to normal- and then realized that the changes follow you when you change themes. Argh! Should I just completely start over from scratch? My main problems are not that huge, but they’re annoying the hell out of me. 1. My site name refuses to use the google font that I want (from Google Font Manager) even though the tagline takes that same font, and the site name and tagline are also all squished together, like there isn’t much space at all between them. Can you offer any suggestions? I know I’m stupid for changing the Parent theme in the first place, but I obviously didn’t realize that that was what I was doing. One last thing is that I’m wondering how I can get the layout of my website to look like the layout that’s used in the theme example- should I contact the people who created that theme for help with that (since I can’t seem to do that on my own either-so frustrating-I swear I’m not stupid, but this stuff gets a bit confusing).
Thanks in advance for any advice!!