I noticed what looks like an air bubble/blister on my right breast incision site. What is this? (photos)

This Is perfectly normal and will disappear in the next few weeks. It is from air and fluid (irrigation, local anesthetic, serum, etc) in the pocket which will be naturally absorbed over time.

This appears to be a suture which is spitting through the skin.  This needs to be addressed by the plastic surgeon.  It is common with absorbable sutures.

Hi.. thank you for the question and photo.... it seems to be a spitting stitch going thru the skin. Go see your PS, for the treatment, and there is no reason to be worried.  

This is often due to how your incision heals. This can be revised and may heal better. Best of luck.

Recommend evaluation by the surgeon that performed your breast augmentation. However, blisters and raised areas along the incision several weeks to months out are often the result of absorbable sutures that the body is breaking down by inflammation causing the response you are seeing.