Half of my smile is normal and the other half is gummy. Is there any way to fix it? (Photo)

There are several issues apparent from your photo.  You have a narrow V-shaped maxilla especially apparent on your left with the dark buccal corridors but present on both sides.  The anteriors are rather prominent and there is a maxillary cant.  
I would suggest utilizing a DNA Appliance and Epigenetic orthodontics/orthopedics to widen the maxilla.  A wider maxilla would give better bone and tooth support to the soft tissues of your face.
It is possible with Cranio work to correct a canted maxilla but it must be part of a treatment plan.
It is possible to surgically alter gum levels but I would not Rx for you.  Botox, I also do not RX but it could limit height of lip when smiling.

I would definitely not recommend Botox. Your lips are level and it would make them appear crooked when you smile. There are ways to change the look of your teeth and gums on your left side to make both sides look similar. I would suggest going to a dentist with experience in cosmetic treatment for an evaluation.