Why did the poet lament in the poem, "Oh, I Wish I’d Looked After Me Teeth"?

Why did the poet lament in the poem, “Oh, I Wish I’d Looked After Me Teeth”?
or
Why was the poet sad in the poem “Oh! I Wish I’d Looked After Me Teeth”?

The poet was negligent and careless during her childhood. She enjoyed candies, lollies, sherbets etc. As a result, her teeth are damaged now. The decay had given
way to cavities. Painful injections and visits to the dentist have become her routine. That is why she is sad.