First and foremost, tell your landlord about the mice infestation. Your landlord should be responsible for the infestation and they might call a professional pest control team to deal with the mice issue. Second, try to investigate how mice get into your apartment and seal every crack or hole that mice could sneak in. Keep your apartment clean and store your food properly. Without source of food, mice would not be attracted to your apartment. Then, set a mouse trap or bait and check them regularly.
If there is no improvement after all of these methods, you might consider moving out of your apartment. Mice tend to live in groups. If you see one in your apartment, there probably is more and more. They can carry and spread bacteria and bring much worse result than you could imagine. Therefore, move out as quickly as possible!
The information in this answer is general in nature and is not legal or insurance advice for your specific situation. Policy language varies carrier by carrier; your declarations page is the final word. If you're unsure, call your agent before you need to file.