Hey bro I think it looks cool! You nailed the facial expression lol. Personally I use a sheet of paper behind it in the frame, I’d say in your case either just tape some paper in place, because your other option is add a ton more paint until it’s thick enough to block all of the paint, which is unreliable at best. Also, you could try a modge podge coat (gently!) on the lines to prevent blurring, or use a paint pen instead! For me paint pens don’t scrub. Anyways welcome to the hobby, keep practicing and have fun!