Good evening and welcome to Just Answers.
have you been to the emergency room?
IT sounds like you are allergic to the sting. Even though you have not gone into anaphylaxis, you are still in danger of that. The swelling of your neck represents a strong possibility that you could have a compromised airway and it can become serious. That swelling is caused by antihistamines produced by your body and the accumulation of fluids in your neck tissue and lymphatic system.
A delayed allergic reaction more serious than you have already experienced can be very serious to you. the benadryl is good, but you may need more powerful drugs such as cortisones or a shot of epinephrine to reduce this.
A physician would listen to your airway internally,using a stethoscope and would determine if you were having a compromised airway and the need for stronger medications.
I would not want to see you go into anaphylatic shock in your sleep tonight that could be lethal.
I would apply ice, and got to the emergency room right away.
also while you are there, you can ask the doctor for a prescription for a beesting kit for you to keep withyou.