Please help with Hugo art (first timer here)

I’m trying to make some stick art of Hugo. This wonderful image was done by ViciousSLASH and I’m attempting to color it in. I saw this really cool avatar of Hugo and I want that same effect on mine. It’s like this rainbow glow around him. Can someone add this for me please?:angel: :angel:

Here is the original:

Here is the colored version I made (FIRST TIME EVER!! :D)

And here is a pic of that avatar with that real cool glow effect.