A person who suffers from OCD (Obsessive-compulsive disorder) and repeats words in davening, and he was told by other people never to repeat words even if he knows that he said something wrong – may or should he, in fact, refrain from repeating words even if he knows for certain that he said something wrong or made a mistake that requires him to daven again?
May one, in general, repeat words in Shemone Esre due to having said them without kavana, or not having said the word correctly, as is common, perhaps, when a person davens SE quickly.

A. Please see question 366 in this forum: I would like to clarify if it is permissible to recite a posuk with Hashem’s name as often as one wishes (repeating the posuk with Hashem’s name multiple times) not as a tefillah necessarily just as a reminder to someone or for an other purpose?

A. Horav Shlomo Miller’s Shlit”a opinion is that you can repeat a posuk with Hashem’s name multiple times as long as it is done in a respectful manner and does not create a Hefsek during Tefiloh or a similar situation.

See also question 671 If someone is overly careful to pronounce the words of the shema properly and keeps on repeating them many times, trying to get it just right, is that not a hefsek? Thank you

A. Horav Shlomo Miller’s Shlit”a opinion is that it should certainly be avoided. One should train himself to recite the words properly and with the correct grammatical expression the first time. Additionally, it may occur that when repeating the word several times, in the end only part of the word will be recited properly or not at all, resulting in the non-compliance of the mitzva.
However, in regards to all brochos (not just words) of any part of davening that were recited without proper kavana (excepting the first bracha of the amida) one does not repeat them.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a