If you see paint stroke now, same will happen if you use a paint brush to redo it. With a paint brush you have to built thin layers to get it smooth and even then its still hard on a sculpt.
Best thing to do is use a airbrush, or a can of spray paint. Taymia makes paints for a airbrush but also makes small can sprays which could work for the red boot. But would need to mask it off.
For the white same thing, would need to do the boot first, then mask off and then paint the white.
I did a two part video on masking with Silly Putty that might help you out
https://www.youtube.com/watch?v=8yY6LmgDC40
https://www.youtube.com/watch?v=oNfGT840NMY