FIRST: Is this an electric dryer or a gas dryer? IF IT IS GAS CALL FOR HELP IMMEDIATELY
What to do if Your Dryer Smells Like Rotten Egg
Experts recommend leaving the house immediately if you smell rotten eggs near a source that uses natural gas as a fuel. That's because a leaking gas line can lead to explosions if it's allowed to build up in sufficient quantities. Leave the house and do not turn on or off any lights. Doing so may cause a small spark that could ignite the gas. Do not use cell phones or door bells, or anything with an electronic switch. It's also important not to smoke around gas lines or leave open flames near them. Call authorities immediately if you suspect a gas leak. Most fire departments are trained in detecting and sealing a gas leak. Your utility provider may have more information on who to contact in the event of a leak.https://www.hunker.com/13410192/my-dryer-smells-of-rotten-egg
Mercaptan is a chemical added to natural gas which smells of sulfur or rotten eggs so you can detect a leak. It may be a small leak, but it is never safe to have leaking gas. Better safe than sorry - make the call to your fire department or utility company now!!
If it is an electric dryer, it usually means you have some debris or slimy buildup. Check around and inside all of the rubber seals and clean with bleach. Also check thoroughly for any built up lint inside the machine that may have been rotting.