What should I be watching for after baby was stung by a wasp?

Breathing problems. Biggest worry with any kind of allergic reaction is breathing problems. If there is swelling of the face, lips, or eyes then go to the er or doctor immediately. If wheezing or labored breathing or gasping for air then call 911/go to er. However most stings just cause an local reaction at the site of the sting - swelling, pain, redness, warmth. Treat with cold compress, tylenol, (acetaminophen) and Benadryl cream.