Bless your heart.
Kudos on the peroxide - it needs to be food grade though.
I'd definitely take the child to a chiropractor. . .
Also - what about lymph massage? This could help a lot. I don't know where you live but I've found that most massage therapists can refer to a person who specializes in lymph massage.
Here's what I found out from my Prescription for Natural Healing Book:
Very Important: Colloidal Silver - (take as directed) natural antibiotic - can be taken orally or as an ear wash (look for it in an herb shop or a grocery store that contains fresh herbs (dont buy herbs at places like Walmart - they're dead - you'd be throwing away money)
Very Important: Manganese - 10 mg daily (adult dose) - deficiency has been linked to ear disorders. (do not take as same time as calcium)
Very Important: Vitamin C (childrens dose is 200 mg 4 times daily) boosts immunity and fights infection (there are chewables for children). Use an estrified or buffered form such as Ester-C or calcium or zinc ascorbate.
Very Important: Zinc - 10 mg lozenge form daily for 5 days, then 50 mg daily in pill form. Do not exceed this amount (this is adult dosage - take it down quite a bit for a four year old).
Also Important: Kyolic - EPA from Wakunaga (as directed on the label) to reduce inflammation and infection.
Also Important: Vitamin B complex (adult dose is 50 mg of each major vitamin 3 x daily) - DO NOT TAKE AFTER LUNCH - THIS CAN KEEP YOU UP AT NIGHT - ITS AN ENERGY BOOSTER - will also turn pee bright yellow - important for immune function.
Also Important: Vitamin E - (adult dose is 200 IU daily) - enhances immune function. Use d-alpha-tocopherol form (side note: Ive read if you dont get the d-alpha-tocopherol form, you might as well not even take it - if it's not in this form then it's man made. Man made vitamins and herbs are not desireable).
To alleviate pain: place a few drops of warm garlic oil or olive oil in the ear, then a drop or two of lobelia or mullein oil. You can plug the ear loosely with a cotton ball. You can also make a paste using onion powder or clay and warm water, and apply the paste to the outside of the ear to relieve pain.
Olive leaf extract helps the body fight infection.
Avoid the most common allergenic foods: Wheat, dairy products, corn, oranges, peanut butter, all simple carbs, sugar, fruits, fruit juices.
Apply hot and cold compresses alternately to the scalp just behind the ear.
HOMEOPATHIC REMEDY: (I use homeopathics on my four year old ALL the time - they are completely safe for everyone - even infants and pregnant women) - Earache Tablets from Hylands' Inc - a herb shop will have these - sometimes walmart or a groc. store carries them too - they contain Belladonna, Calcarea Carbonica, Chamomilla, Lycopdium, Pulsatilla, and Sulfur.
And. . .I know you've been to the doc more times than you should have. Maybe they're not getting it. You may have to be very forceful, maybe it would help to tell them noone in the house is sleeping, she is in severe pain, and you MUST receive help. I dunno, you may have already done this. The thing is, they have failed you thus far - this baby has been hurting waaaay too long and you're having to diagnose and treat your own child which is not right when you have been to so many doctors.
Perhaps you can find a naturopathic doctor?
I know that a good chiropractor could probably tell you what's going on.
Good luck to you - I hope some of this helped.
Edit: something else just occured to me - There's no way there's a bug, or a toy, or something else in there, right? I mean, I know that 4 year olds are curious and he/she learned that the doc can look IN her/his ear. So, now the child knows there's an "ear hole". I could see how a kid could go sticking something in there playing doctor afterwards - just a thought.