Pain and swelling from cheek retractor in teeth whitening procedure days on. Help! (Photo)

Thanks for the question. I can tell you for sure that your swelling is not from the stretching of the cheek retractor. That amount of swelling is a reaction to some substance or material that you are sensitive to. Essentially it is contact dermatitis from your lips touching something that your body does not see as acceptable. It could even be an indication that you have developed or are developing an allergy to whatever came in contact with your lips. It could be latex, or it could be something the technician had on their hands. Try some Benadryl cream/ointment to help with this episode and make sure you inform your doctor/dentist in the future that you had this reaction. If you are able to see an allergist and get tested, this would be best but if the cost prohibits this, be sure to indicate that you may be allergic to latex at future visits until you can confirm what the reaction is from, or the next exposure may cause a stronger, potentially life-threatening response. Good luck!

two possibilites here, First it  could be a burn from the solution or second it could be an allergic reaction. I would continue icing, take Advil every 4 hours and take some Benadryl at bedtime. Hope you feel better.