Hole in dogs eye, help!

A friend of our family passed away on Friday. As she wished, we took in her 3-year-old female Shih Tzu, Bebe. We already have a 12-year-old male Westie and a 3-year-old female cat (unsure of breed). Bebe is traumatized by all the sudden changes and terrified. The dogs get along fine, but my cat became possessive and hostile, which is unlike very her. They crossed paths and my cat took a swipe at Bebe, and caught her in the eye. We took her to the vet today and he said there was a "hook-like" hole in her eye from the cats claw, but if we take good enough care of it (with the medicine he gave us) she should be fine. Is this true? Or is he trying to make me feel better? I'm so worried about her