I tried editing my skin with paint.net but the format was sadly cpmprojekt which pant.net obviously doesnt support.

png would also work btw

If you uploaded it to Minecraft.net then you can get it here:
https://minecraftskinstealer.com/
... and anyone's skin for that matter...

In the future, try asking the discord server. We'd be happy to help and you would get a much more prompt response. This issue board is for bugs and suggestions.
https://discord.gg/mKyXdEsMZD