What can be done about my very recessed chin? (photos)

You have an underdeveloped jaw that would likely benefit from orthognathic surgery. You should consult with an oral surgeon to see if jaw advancement surgery would benefit you the most. You can also consider surgery as described by others answering this question, but a good oral surgeon can take Xrays and measurements of your jaw and recommend the best treatment for you. At the very least, you may consider a chin implant which is less surgery, but probably the easiest and quickest results. Best of luck to you.

 The photographs demonstrate a weak and recessive chin profile along with fatty deposits in the neck. A chin implant can be placed through a small incision underneath the chin to give added projection to the chin and help with facial balance and proportions. Liposuction of the fatty deposits in the neck will help improve the jawline and is complementary to the chin implant. For more information and many examples, please see  the  link and the video below

Combination of moving the chin forward and and slightly down along with a sliding osteotomy of the chin and removal of fat from under your the chin and contouring the other structures of the neck is a very powerful technique and would serve you tremendously.