You should follow food safety tips to decorate Easter eggs

When you decorate hard-cooked eggs or emptied eggshells, be sure to follow these food safety tips:
Wash your hands well in hot, soapy water before handling eggs at every step, including cooking, cooling, dyeing and decorating.
If you want to eat decorated hard-cooked eggs:
Refrigerate hard-cooked eggs whenever you’re not working with them. Put them in their cartons if you won’t be decorating them right after cooking. Refrigerate them again right after dyeing or decorating them.
Make sure the eggs you color aren’t cracked. If any crack during dyeing or decorating, throw them away. Also throw away any eggs that have been out of the refrigerator for more than 2 hours.
Use food coloring or specially-made, food-grade egg dyes. Dissolve the dye in water that is warmer than the eggs. Be sure the label says nontoxic on any crayons, pens, paints or other art materials you use. Or, use edible decorations like herbs. (You can use any art materials you like if you’re not going to eat the eggs.)