PMS- help!

Most of the time when I’m pmsing, I get one tiny little dot in the corners of my mouth. You can’t see it. If I look in the mirror, look closely and open my mouth I can see it! I’ve heard it’s normal. As a lot of women get canker sores and swollen gums and dry mouth. It’s one of my biggest complaints with PMS. Can anyone relate and have any solutions?