Eye Bags and Swelling 8 Months Post-Blepharoplasty

I concur with the other recommendations and highly advise you seek an additional opinion by a board certified plastic surgeon, oculoplastic surgeon, opthalmologist, ear nose and throat physician, and/or internist.
Swelling of the lower eyelids has a variety of causes and surgery is not always the answer:

This includes condition such as thyroid disease.
If the condition is caused by inflammation antiinflammatory medications and drops may be beneficial.

Surgical treatments may produce improvement but other causes should be thoroughly evaluated first. It is difficult to tell if the swelling in your lower eyelids is due to extra fat (surgically treatable) or to edema. If it is the latter you may see improvements with facial manual lymphatic drainage.

It's not unusual for patients to experience swelling following blepharoplasty surgery. In some cases, this swelling may be prolonged and take time to resolve. Although swelling is the most likely explanation for the puffiness of your lower eyelids, other explanations may also be possible. In this case, it's possible that not enough fat was removed at the time of the original procedure.Although your history is helpful, it's virtually impossible to make a specific recommendation without a physical examination or pictures. Even a physical exam might not totally clarify the issue. It's also important to rule out medical conditions, chronic irritation and allergies.In someone who's eight months post-op, it's probably reasonable to consider revisional surgery if the medical workup is negative. For this reason, it's probably reasonable to obtain a second opinion as well.

You may have swelling even after 8 months.  This is unusual but not unheard of.  These vitamins and creams you are using are ineffectual and I would skip them if I were you. 

It is possible some additional fat might need to be removed especially from your left eye.  But it is too early to make that judgment.  As long as you are making some progress, albeit modest, observation should continue.