My daughter is missing the enamel on at least half her baby tooth - can anything be done if its this severe?

She had a fall last year and had to have one of her front teeth pulled due to damage. I dont know if this is delayed or the result of neglect on my part which is entirely possible. I am just wondering can it be fixed in any way at this point if half her tooths dentin is exposed. I feel so bad about this - as in worst parent ever.