Even if skin tags are harmless, this is not to say that you should allow them on your skin. They should still be prevented because they can be quite irritating. See How to prevent skin tags?:
1. Reduce skin to skin rubbing: Avoid skin to skin rubbing or your clothes rubbing against your skin. And wear clean clothes.
2. Decrease skin fold: This can happen by losing some weight.
3. Prevent diabetes: Those living with diabetes have a greater chance of having skin tags.
4. Freezing kit: You can get them from drugstores around you. They possess liquid nitrogen that can be used to freeze skin tags.
5. Tea tree oil: Used to care of several skin conditions, skin tags is one of them.