What do you have to watch out for if you want to be sure you are not running any risks?
First of all, make sure that the cosmetics you are selling really are cosmetics and not watercolour paint or a product for special effects. Such products may look like cosmetics, but do not comply with the safety requirements of the EU Cosmetics Regulations at all.
Choose manufacturers who publish safety information sheets that cover the following:
the ingredients and their maximum percentages
the shelf life after opening
the minimum shelf life