Received half a Syringe of Restylane (0.4cc) to treat both tear trough areas...Not sure if it was enough

Hi Delilah.  We typically use between 1-2 CC's for this procedure so .4 is a very small amount.  What you were seeing was probably swelling.  Was the treatment done with a technique called "under the muscle"?  If not, I would be concerned about getting more injected as this is a very technique dependent area.  If your injector is placing the product deep in the skin under the muscle, then by all means go back for more.  If you only get .4 CC's you may not see value past a few months.  We inject 1-2 CC's to get patients 6-12 months duration.  Good luck.

It sounds like you were under-dosed and it was mostly swelling that you saw the first few weeks, I do suggest you have another syringe to see full result 

0.4cc is a very small amount to the tear troughs.  I typically use cannula injection or depot on the bone in this area and get good results, but use much more than 0.2cc per side.  You may also consider a different filler such as Voluma which gives a little more lift if you are truly "hollow."  Without photos it is very difficult to give a great opinion.  However, I do agree with the other responses that an expert injector, someone with a lot of experience and significant background, is required for treating this area.  I wish you the best of luck, Dr. Emer.