I have been unable to find a record of his service, this came from a Goggle Search

George B Twyman

Basic Information
Name
George B Twyman
Birth
abt 1820
Frankfort, Franklin, Kentucky, USA
Death
After 1891
Higginsville, Missouri
Time In Service
From: 1861
To: 1864
Affiliation
Allegiance
Confederate States of America (American Civil War)
Branch of Service
Infantry
Rank
Private
Unit(s)
Specialty
Wagon master
Current Status
Not Specified
Service Record
War
Civil War
Battle(s)
Honors & Awards
Award(s)
Not Specified
Private,"B" Co., Irvin's Reg., 8th Mo. Brig., Rain's Div.

1861-1864
George B. Twyman's application for admission into the CONFEDERATE HOME OF MISSOURI, George stated that he was mustered into the Cass Co Mo service as a private in Company B --- Bradley under Col Irvin's Regiment Eight Missouri State Guard Brigade Gen Rains division.George stated he was in the battles: from Morrestown to Pleasant Hill, from there to Osale, Mo. " then I was put on as Wagon Master of General Rains Ordince trains. I was transferred to General --Rains as company wagon master regiment train Brigade at the Battle at Pea Ridge on 6 Mar 1862 and while in this command served in the following marches and battles. Battle of Morristown. When General Rains and General S Price crossed the river they sent me to Leman Co. Texas with the wagon train & horses. I remained at that post til General Rains returned to frey 1864 --there I assisted the quarter master in getting up wagons."

https://www.ancestry.com/family-tree/view/Military.aspx?tid=1574802&pid=-1918034534&vid=2928e16e-18ec-48e5-bd6e-442dd503eee4