Non prescription colored contact lenses are much the same as prescription contact lenses. As long as you care for them properly and do not over wear them (only 6 days per week), you should be ok.
The chances of something bad happening are about the same as those that wear prescription lenses. They are minimal if you do the right things.
Always wash your hands. Replace the lenses when you are supposed to. Do not sleep in them. Do not wear them when you have a cold. Do not get water in them and clean them thoroughly. You should be ok.
If you are wearing them long term then have regular eye tests too