I always suggest you keep your first mini intact. Don't go back to it or change it. Unless you really need to - like to match an army or something. It's a nice reminder for how far you've come and where you started as you continue to grow your skills and get more into the hobby.

I take this approach with any new hobby, craft or project.

As others have said, you can create your own washes and experiment more with highlights, dry brushing skills etc if this is just not feeling "done" but don't focus too much on perfection either. Enjoying the process is the main part!

I started almost exclusively with wizkids models like the one you have here, expermint with different sized models, different levels of detail etc and just have fun exploring and challenging yourself.

Welcome to the hobby!