Hello, and welcome!
I'm sorry Lucy has you worried!
The little black 'hairs' you see on her chin could be flea 'dirt' (excrement--resembles ground black pepper), flea larvae, which are tiny black worm-like things, or she could have feline acne, which is like human acne with blackheads occurring from blocked oil glands in that area.
Even if she doesn't go outside at all, cats can still get fleas, brought in on shoes/clothing of humans.
If this area doesn't seem to be bothering her, try to wipe it gently with a plain, damp, warmish cloth or paper towel. If you see the 'hairs' moving, you definitely are seeing flea larvae or some other kind of external parasite. If these particles look reddish-brown when they touch the wet cloth or paper, this is flea dirt. If nothing comes off, this might be feline acne.
If your result shows flea-related items, you will need to treat Lucy with a monthly topical flea treatment, sold by your vet, like Advantage, Frontline and others. Advantage and Frontline are now sold over the counter in some pet supply stores, but just make sure they are the right kind for her age and weight. Don't buy the dog ones by accident! Also, don't EVER use Hartz, Zodiac, Sergeant's or any other flea treatments sold in supermarkets or pet stores (except the two I mentioned), as fatal adverse reactions have been seen from these products.
If she may have feline acne (I would recommend a vet visit, to get a definite diagnosis after an in person exam), just keep the area clean and if she's eating from plastic or metal bowls, change to glass or ceramic. You can wash her chin once or twice daily, with a mild soap (plain baby shampoo), benzoyl peroxide, or chlorhexidine.
Here is more information: http://www.peteducation.com/article.cfm?c=1+2141&aid=2517
I hope all will be well with Lucy and please let me know how she's doing and what the vet tells you. Thanks!
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