There's a scene in which Raynor takes Kristen to a gravel pit. He separates a 6-pack of beer and twists the individual cans down into the dirt. Kristen empties a revolver at the cans, hitting four of them. Raynor retrieves the 2 remaining cans and gives one to Kristen. During their subsequent conversation, Kristen plays with the sta-tab on the can, except that the film is set in about 1972, and the sta-tabs didn't go into use until maybe 10 years later.
When talking with Kristen outside the hotel, Dodd's tie is loosened about 5 inches and cocked to his right. When he enters the room and talks with Jimmy, his tie is barely loosened and directly under his throat.
When Dodd talks to Kristen outside the hotel, his tie is loosened about 4-5 inches and pulled to his right. When he enters the room and talks to Jimmy, his tie is loosened about 1-2 inches and directly below the shirt button.
The first time Jim puts a needle in his arm in-front of Kristen, he never pushes the plunger in, when he unties the belt, you can clearly see a few inches of white plunger, if he had pushed it in, the plunger would not be sticking out. So therefore he did not "shoot up". He simply stuck the needle in his arm without injecting the contents.