Sherlock knew he wasn't fine. He just didnt want to admit that. He never could admit when something was upsetting or scaring him. He had tears in his eyes and hoped Lestrade didn't notice. It had been awhile that he had been so scared that he would cry.
Sherlock would sometimes fake being scared if it would help him with a case. Sherlock was a good actor, he could mostly hide things . Though it depended sometimes.
This time he was very scared and it did show through even when he tried to hide it. He was looking at Lestrade. He blushed when he was helped out of the tub as he felt a little awkward . He grabbed a towel and was shaking as he got changed .

His fear was something he wanted to keep to himself if he could. But he had a feeling Lestrade knew. He hoped Lestrade wouldn't ask him too much.
Sherlock really did look dazed from fear though.