Recently through repetitive smashing, I discovered that I had sprained my wrist (opposite of my palm). I believe there's inflammation in my wrist ligaments, because its been over 11 days and I still have not fully recovered.

I was wondering if my sprain was due to my racket, MP99, being head heavy? (or just poor technique)

Is it recommended for me to switch to a head light racket?

Also, does anyone have a vid focusing on the wrist movement during a smash (I think I have poor technique)?

It's probably you have poor technique, and you're overloading all of your force straight into the joint. Likely if you switch to a head light racquet you'll have even less power and will need to add more force, and you'll end up throwing your shoulder and blowing your elbow. Focus on the technique first, then find a racquet to suit your needs.

I really doubt if a few grams of extra weight in the head is causing your injury. You also might want to consider some wrist strengthening exercises once your injury heals as well as trying to use a proper technique.