I have a pea size blood filled bubble on my toe between the nail and skin on the outside of my left big toe its not under the nail what could it be ?

"Blood blister": It sounds like a benign problem likely from some trauma to that part of the foot. Your description sounds like a fluid filled vesicle (blister) with the fluid being blood. Rubbing against a new or ill-fitting shoe, or duirect injury are common causes. Usually just leaving it alone is the best treatment as the body will take care of such things. Popping it increases risk of infection.

Blood blister: You probably pinched the area some how and got a blood blister. Should resolve on its own. If it gets larger, painful, or red, see your doctor.