For over a week i've had painful swelling in my legs with burning sensation and red splotches on my shins making it painful to what can it be?

Erythema nodosum: This sounds like it may be erythema nodosum and can be representative of numerous systemic diseases. With the oral lesions you are describing along with the visual difficulties i would be concerned about behcet's disease. Strongly suggest you see a rheumatologist asap, or start with a pcp and get referred if they feel it necessary or advisable. Do not wait on this. Good luck.