Issues editing theme- Changes not appearing

It's me again... Sorry!

I managed to get everything on a very basic level set up and installed. Now I'm trying to edit the theme but all changes I make just do not appear on my site, no matter how simple (couldn't even get the background color to change). I'm working in Indotherm- whiteout's tone file, editing in TextWrangler. Inditherm-whiteout is definitely installed and assigned, too. Before this I made attempts to test edit Stick Figure and Asterisk just to see if anything on the site at all would change but had the same issue. Tried Dreamweaver too, but that didn't work, either. I know it's not an FTP connectivity problem because uploading files and new themes works, and the changes do appear in the files within the FTP program. So this issue is baffling me a little bit.

I might try duplicating the theme file and editing it, then uploading it as a new separate theme, but with that route I'd definitely end up with a million installed themes in an attempt to edit things. Would definitely prefer to not do that.

Thanks in advance for your help! These forums+your answers have been seriously helpful to me.