Dear Professional Nail Department
Advise on keeping your nails healthy
Your nails are probably damaged because you bite them, and they are probably uneven because you don't trim/file your fingernails regularly. Something that would help is trimming/filing them regularly, make sure you stop biting your fingernails and cut them and also keep them moisturized.
To keep your skin and nails moisturized in the dry weather, make sure when you get out the shower, frequently put on lotion. If you do that daily , I guarantee your skin and nails will stay moisturized even in the dry weather.