Will the left drop to match the right side and how long does it usually take to drop?

It really depends upon many factors  based upon what was done in the OR and how you looked preop.  Implant type also will impact the results as well. You are best to give it time to heal and see how they settle.

Sometimes healing from a surgical procedure can be as tedious as "watching the paint dry". It is not uncommon to have mild asymmetry after a unilateral breast procedure or a procedure where more "work" was done on one side. Be patient and try not to pass judgement on your result for six months after surgery, because it can take that long (and sometimes longer) for the human body to heal and for asymmetries to even out. In the meantime, keep the line of communication with your plastic surgeon open and if it doesn't look right after six months, return to see him/her to discuss your concerns and your options.

I understand that you had a  revision procedure for the left breast and fat grafting on both side. It is not uncommon for one side to sit a little higher than the other. Also the fat grafting has to settle and declare itself fully. I would wear a high quality sports bra and have it reassessed in 6months. Some drop will happen on the left side which may sort this early issue out.
I would certainly give it a little more time and reassess with you PS to take matters forwards.