You should be concerned if people get what you say, if they understand your message and the value it brings; you should not by any means be obsessed with how you do it, because this is more yours than theirs. (Aristotle, 2007; Lucas, 2019; Savitsky & Gilovich, 2003).
The merit must be there, be obsessed about the merit;
let loose on how you will deliver it.
You know the saying about eccentrics: “Yeah, he’s a bit weird, but he’s a genius”?
Exactly, when you are really excelling at something, no one really cares if you sneeze during the speech, turn red or even green, because you delivered the value (Gilovich, Medvec, & Savitsky, 2000).
Obsession over the merit. Chill over the delivery.
People who have little to say sometimes try to compensate with the way they say it, and they become obsessed with their look, etc. (Lucas, 2019).
*I expect some fierce debate in the comments! hahaha
References
Aristotle. (2007). On rhetoric: A theory of civic discourse (G. A. Kennedy, Trans., 2nd ed.). Oxford University Press. (Original work published ca. 4th century BCE)
Gilovich, T., Medvec, V. H., & Savitsky, K. (2000). The spotlight effect in social judgment: An egocentric bias in estimates of the salience of one's own actions and appearance. Journal of Personality and Social Psychology, 78(2), 211–222. https://doi.org/10.1037/0022-3514.78.2.211 Lucas, S. E. (2019). The art of public speaking (13th ed.). McGraw-Hill Education.