Nooooouuuuuhhhhhh…
You surely made the “novice error” every woodwind beginner player makes.
Before taking any action, read about transposing in this forum, or everywere on the net.
The tenor is a Bb instrument. This means that when you play a C (middle left finger key only) it sounds a Bb (or A# which is the same). So if you read a tuner, it’ll display Bb when you finger a C and A when you finger a B. It’s normal. Tenors sound 2 semitones below the written (fingered) note.
The MP adjustments on the neck shifts tenths of a semitone for fine tuning only.
Ggood luck!