I got electricutied at 8 years. I am 25 and I now have fibromyalgia. What is the side effects of being electricutied.?

Electrical injury. Electrical injuries typically have the tip of the iceberg effect meaning that what you see on the surface is only a small reflection of the true magnitude of the injury. The nerve involvement can be very extensive and far beyond the "entry" wound. Urgent care demands removal of necrotic (dead) tissue, with a longer time to assess the nerve injury. Fibrosis is common, fibromyalgia is not.
Back injury? 28yo female electrocuted 8yo & queries relationship to current fibromyalgia (FM). FM associated w. femaleness (childbirth), biomechanical injuries, & Joint Hypermobility Syndrome (JHS). I have seen females w. FM & JHS where only sig. injury was soccer (fallings ages 6-10) & by high school w. chronic debilitating low back pain; later FM. Did electrocution event cause low back/pelvic girdle trauma?
Electrocution. The electric current takes the path of least resistance going along blood vessels and nerves (good conductors) from the point of entrance to the exit. Damage occurs along this pathway including entrance and exit burns, coagulation of vessels with loss of function and damage to internal organs. You are well past any residual effects of this/ fibromyalgia is not a known risk of this.
Fibromyalgia. It would be unlikely for fibromyalgia started now to be the result of electrocution 17 years ago. I would first look into vitamin, nutrient, or hormonal deficiencies.