Does scar tissue cause nasal valve collapse? If scar tissue is blocking breathing will it go away and when?

At three months after your surgery you still have swelling present in your nose that can be causing your nasal obstruction.  Make sure that you follow up with your surgeon and express your concerns.

Dear taylor,
thank you for your question. Breathing problems after rhinoplasty may be
related to swelling, crusting, or mechanical obstruction. Consider following up with your doctor
determine the cause.If you are not
satisfied, a second opinion may shed some light. Best of Luck.

In order to perform any rhinoplasty, the surgeon must make incisions inside the nose for access. These incisions create scars. All scars change with time.
I would allow more time before you decide on whether you like the aesthetic result, or on the final functional (breathing) outcome.
Results take at least 6-12 months to determine. More consults will not help you; time likely will.
If, after allowing adequate healing time, your breating results do not improve, surgery will likely be necessary to improve the issue

12 weeks is early after rhinoplasty and difficulty breathing through your nose is a common phenomenon after any rhinoplasty.However the fact that elevating your nasal tip improves airflow through your nose may suggest that an internal nasal valvular obstruction exists.  Please see your plastic surgeon and ask if you have did internal nasal valve obstruction.  If you do surgery may be needed to correct it.

 Hopefully things will improve over time.  It is possible that you have nasal valve collapse that may need treatment if no improvement.  But I would give it longer period of time to see.  Close followup with your surgeon.  Good luck.  Donald R. Nunn MD  Atlanta Plastic Surgeon.