Breast revision surgery after breast reduction about 7 years ago?

It is difficult to completely answer this question because you didn’t mention whether your breast increased or decreased in cup size over time, just that the difference between the two increased. Regardless there are three facts to be aware of. First, no woman has breasts that match each other in size or shape. This is normal. Secondly, breast volume and shape will change with changes in weight, because a certain percentage of the breast is fat. This is most likely the cause of the changes in your breast cup size. The last fact to know is that a breast lift may not hold its position forever, and may need a revision at some point later in a woman’s life. It sounds like you have reached that point. My suggestion is to contact your original surgeon and request advice from him or her in how to proceed.
Finally, my experience has been that insurance will not cover much that has to do with appearance, but it may be worth asking the doctor who you choose to revise your breast to check on the policy of the insurance company in that regard. Good Luck !

Yes a revision is certainly possible and after 7 or so years may not be inappropriate. Aging, gravity and weight changes (among other factors) all have an impact on breast shape. In the past few years there have been some advances in breast lift/reduction techniques using absorbable mesh which can offer excellent long term results and breast support. A consultation with your plastic surgeon can give you specif details of what would be best for you.

Insurance coverage is an unknown factor. Each policy has its own provisions and each carrier has their own criteria what what constitutes a "covered" expense. In my experience, it is improbable that most insurance companies will cover this particular procedure.

Best wishes!

Revisions can be done. In order to make a specific plan for you, consultation and examination would be extremely important. In addition, any information you can obtain about the type of reduction technique done is very helpful. That information would be in the operative report from either your prior surgeon or the facility where the surgery was done. In general, it is easier to raise a nipple than lower one. In terms of insurance coverage, you would have to generally qualify for the same criteria as before for a breast reduction or most likely end up having to appeal a revision. This all depends on the type of insurance you have and the company. Try to get yourself a case manager with the insurance company rather than simply asking about your benefits.