His records seem somewhat disjointed and from two sources. This is the best I could piece together.

…..

Samuel Parker, Surgeon in Charge, Ward I, Macon, June 15, 1862, Assistant Surgeon, Field & Staff, 3rd Regiment Arkansas Cavalry, appointed September 4, 1862, assigned to duty with regiment, September 24, 1862, stationed at West Point, Miss. March 8, 1863, died July 14, 1863, [?]. H. Fowler filed claim for the settlement of his accounts September 16, 1864, no other records

Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Arkansas
&
Compiled Service Records of Confederate General and Staff Officers, and Nonregimental Enlisted Men

……………………

Samuel Parker, Mississippi, Assistant Surgeon, Medical Department, Provisional Confederate Army

Confederate Officers
By Arthur Wyllie

https://books.google.com/books?id=867sVhrVSzUC&pg=PA393&lpg=PA393&dq=Confederate+surgeon+Samuel+Parker,&source=bl&ots=lzQ_f8gJBV&sig=0gLWK2hM-qcE63YPyU72ezIktj4&hl=en&sa=X&ved=0ahUKEwj5tOr-8vXUAhVJ_IMKHQPBDYEQ6AEILTAB#v=onepage&q=Confederate%20surgeon%20Samuel%20Parker%2C&f=false