Downsize 350/325cc HP breast implants (34D) to small C for petite 31 yo Asian female 5'2" 115 lbs (very self-conscious) (Photos)

Thank you for this complex question.  Decreasing one cup size on someone with a 34D bandwidth equals approximately 200 ccs.  However, this is a very simplistic way of looking at a more complex problem.Questions that need to be answered:  how many children have you had, do you smoke, do you have medical problems of any kind.  It would be helpful to see pre-operative pictures of your breasts 1.5 years ago.  Your external scar makes me wonder if you have some degree of capsular contracture, although external and internal scarring does not always correlate.  Was your breast augmentation a moderate or high profile implant.  These and more questions need to be answered before any of your RealSelf online team of plastic surgery experts can answer your very challenging questions.Since 350 cc implants are not very large, it is possible that the side boob that concerns you may have pre existed to some extent, and therefore reducing the implant may not bring the breast tissue in from the sides.  This, of course, can be determined only with an in person examination plus the above questions answered.  If you were my patient, and if certain of my assumptions are correct, then you may need an internal capsulopexy, both inferior and lateral, to decrease the breast implant pocket.  This can best be handled through a periareolar incision (around the areola).  I would highly recommend you consider discussing this with your previous plastic surgeon which would certainly be a good starting point to help you in your decision process.  

I am sorry to hear about your concerns after breast augmentation surgery.  Yes, you should be able to undergo downsizing of breast implants.  Keep in mind as you are thinking about your goals that sometimes adjustment of the breast implant pockets (capsule adjustments) may be necessary to achieve the outcome you are looking for.   Breast lifting is not necessary.
Generally speaking, the best online advice I can give to ladies who are considering revisionary (downsizing) breast augmentation surgery is:
1. Concentrate on choosing your plastic surgeon carefully. Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals with your plastic surgeon. This communication will be critical in determining breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as “natural” or "down a cup size” etc means different things to different people and therefore prove unhelpful.
Also, as you know, cup size varies depending on who makes the bra; therefore, discussing desired cup size may also be inaccurate. 
3. Once you feel you have communicated your goals clearly, allow your chosen plastic surgeon to work with you in determining the best plan to achieve your goals.
I hope this, and the attached link (dedicated to revisionary,  specifically downsizing, breast augmentation surgery concerns), helps. Best wishes.