My 2 year old daughter has suffered from severe viral conjunctivitis now she is unable to open her eyes due to light sensivity, how can I help her?

Have her checked. She needs to be seen by an ophthalmologist.
See Eye MD. Light sensitivity is common with many eye disorders, including conjunctivitis. I would be concerned that she has a keratitis or iritis if the light sensitivity is severe. Take her to a pediatric ophthalmologist.
See doctor! See an ophthalmologist, your situation is very concerning. You need to make certain it is only a viral conjunctivitis and it has resolved. Other possibilities could be herpetic, uveitis, corneal ulcer. Preservative free tears will not hurt.
Artificial tears. Cool compresses and artificial tears can be soothing.