1 week Post Op Breast lift surgery. I have really dark purple bruising on my left chest versus my right. How long will it last?

It is not uncommon to have bruising after surgery.  It is also common to have some variation from one side to the other.  I wouldn't be concerned about it being on only one side.  Bruises typically take about 3 weeks to resolve.  I have had some patients that have had success using Arnica, which is an herbal treatment for bruising.  It is commonly found at most pharmacies.  It might be worth a try if you want to speed the process along.  Good luck.