If you're all out of masks and/or can't find any in stores, make your own. This DIY mask uses materials that you probably already have at home. Overall, there is disagreement about the effectiveness of masks, but I think that if you must go out, something to cover yourself is still better than nothing, and at the very least, it will remind you to not touch your face/nose so much, and remind you to stay vigilant.
Please note that this does NOT prevent you from getting ill, but what it DOES do is add an extra layer of protection only.