The important thing to remember is that Doolittle thought his raid was a failure. The damage done was minimal and not worth the loss of airplanes. He fully expected to be court martialed, lose a rank, and an otherwise successful career would end in disgrace.

He never considered the psychological effect the raid would have. The raid boosted morale in the US because they finally landed a punch. The raid was demoralizing to Japan because it showed that the US was capable of staging an attack and they were now vulnerable. It is now considered a masterstroke of genius because it send a shivver up and down Japan. The US was not going to capitulate and sign a peace treaty. The US proved it could mount an attack, no part of Japan was safe, and Japan had no way of knowing how many bombers the US could deploy. Would this be a one-time thing? A weekly thing? Nobody knew.

After the raid, he didn't know he was promoted two ranks. He didn't know the President would be submitting his name for the Medal of Honor. He just knew that the raid was exposed early, it did little damage, all of the planes were lost and the men he was responsible for were missing. By launching early, Japan assumed the raid came from a battle group closer to the shores of Japan, and when they launched a retaliatory attack, they were looking in the wrong place, saving two aircraft carriers, four cruisers and eight destroyers from attack.

This also convinced Japan to stage a raid on Midway earlier than planned, which helped lead to the first major victory for the US, depending how you feel about the Battle of the Coral Sea.