Betta hasn't regain his color after recovering from Septicemia?

My Male Betta had Septicemia a week or so ago and I treated and he seemed to get better his color started coming hindmost but is still not his full vibrant color. He was a beautiful Dark blue nearly purple color, now he is a blue brown color. I lately did a water change(also changed water after finishing meds). What is wrong? Is it normal for it to pinch so long for his color to come back?
Blood Parrot Cichlids and Angelfish?
Answers:    its ok it takes time
How oodles fish fit inside this cistern?
Good job on the successful treatment of a tricky sickness!

Sounds to me like the fish is just stressed.. give him another week or two to regain his strength and you will promising see his colors come back.
Why did my fish died? read the details first?   Where can I get hold of a siamese algae eater?   What's near these catfish?   HELP my fish are lying on the bottom of the cistern ?