Is this minor double bubble worth fixing? Will it get worse? Once it is fixed, will it happen again over time? (Photo)

As your condition is only apparent when your arms are raised, most patients would not chose another surgery to correct this. This however is a very personal issue and some patients are bothered by this enough to proceed with the revision. Surgeons will generally assist in the costs. You should feel free to discuss this with your surgeon. 

I do see what you are referring to.  If it was an easy fix it might be worth fixing but it’s not so simple.  As long as it is stable and doesn’t get worse I would leave it alone.

Hello,The breast you're concerned about has an implant that is roughly in the right place. The breast you don't mention has an implant located too high. This is giving an asymmetrical appearance to both nipple position and upper pole fullness. Don't do anything if you can't pay for it, and make sure your surgeon is an expert in revision surgery with at least a decade of experience. If not, it won't serve you well to go back. 

Dear daenerysstormborn,
though rare, some women who undergo breast augmentation will develop a minor deformity known as a “double bubble,” in which additional folds appear underneath the breasts due to the implant accidentally shifting or contracting post-surgery. In most cases, the implant simply slipped too far down the chest wall and traveled behind the breast inframammary crease (the area where the lower breast meets the chest), instead of moving forward to fill the breast cavity. If left untreated, the lopsided implant will form unnatural indentations, resulting in an odd “four-breast effect” rather than the full, rounded chest the patient initially desired. If this bothers you, I suggest you to consult your plastic surgeon and get an examination. 
Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

Thank you for your pictures and question.  I see what you are referring to when you raise your arms but the situation isn't that bad so as long as it doesn't get worse you could leave it as is.  If it really bothers you though then a surgical correction could fix this. Best of luck to you

My personal preference for this type of revisionary breast surgery  would be: raising the inframammary fold using capsulorraphy techniques. In my practice, this type of repair involves a two layer, permanent suture repair (reconstructing the inframammary fold areas).   Additional maneuvers such as scoring of the capsule (capsulotomy) may be helpful when it comes to improving overall shape/contour of the lower breast poles.
Sometimes, depending on factors such as quality of skin along the lower breast poles, additional support provided by acellular dermal matrix or biosynthetic mesh may be very helpful. I have also found the use of acellular dermal matrix very helpful in cases where the skin/tissues are very thin and in cases of recurrent breast implant displacement. The acellular dermal matrix helps improve contour, improves irregularities caused by the underlying breast implant and/or scar tissue, and provides additional support ("sling" effect) for the breast implants.
  My general thoughts regarding the potential need for revisionary breast surgery:  I advise patients to carefully consider their degree of concern with the outcome of the initial breast surgery and weigh these concerns against the potential risks/complications associated with the planned revisionary breast surgery.   For example, if the patient is concerned about her breast appearance on a daily or frequent basis, it is likely that revisionary surgery will be helpful when it comes to improving her quality of life.  On the other hand, if the patient's degree of concern seems minor and/or she is  infrequently concerned about the areas of concern, I would recommend against revisionary  breast surgery.
 Policy regarding coverage of expenses for revisionary surgery will vary from office to office and probably on a case-by-case basis as well. Costs of revisionary surgery may range from zero, to anesthesia/surgery center fees, to discounted surgeon's fees.
 Best wishes.