I just found your post from two weeks ago so I don't know what action you have taken but wanted to reply anyway.

The medical term for this structure is vermillion tubercle. The by-the-book answer is to keep students with this physical feature away from trumpet and french horn. However, I would like to relay an experience regarding this conventional wisdom.

I knew a student who had the upper lip teardrop but started in sixth grade band on trumpet in a school district where there was one director for grades six through twelve. In the absence of individual instruction and evaluation there was nobody to guide him to a different instrument. He was able to adapt by producing a “side aperture” by shifting the mouthpiece to the left of center (shifting right of center is also okay depending on the preference of the individual).

Long story short, in high school the student placed first on trumpet at area auditions. Whether this is an unusual and rare story of adaptation to a disadvantage or a case of totally doable compensation that allows the student musician to reach their full potential I can't tell you. If the student had attended a large, well staffed band program he likely would have been started on a different instrument. He actually benefited, on this occasion, from not having an attentive music educator evaluate his chances of success on trumpet. You can't make this stuff up. Would he have succeeded on euphonium or tuba? Very likely.

I know that some bands shift trumpet players that are showing less promise to low brass after the first year. Again, I don't know what action you have taken with this student since posting but if the student expressed disappointment at having to change instruments I would encourage you to consider giving this more time and start by seeing if the side aperture adaptation described above demonstrates promise in this case. Best regards.