I just noticed a yellowish white blob forming on the inside of my nose. Is this a sign of infection? (Photo)

It may be a small suture abscess.  This is also the location of dissolvable sutures that will gradually come out.  You can gently clean the area with warm saline or dilute hydrogen peroxide and a q tip if your surgeon agrees. 

I think it's important to see your surgeon. In these instances I think topical and oral antibiotics is best. It could be just a reaction to a deep suture but playing it safe after rhinoplasty is always most prudent. I wouldnt manipulate it too much so the incision stays intact. 

Your photo is not clearly demonstrating your concern. Infection 2 weeks following rhinoplasty would be uncommon if no permanent foreign bodies (implants or sutures) were used. If you have a localized tender area, it could be a foreign body reaction to a suture, or a local suture abscess that could be addressed during an office visit. In that regard, please notify your surgeon and make a follow up visit as soon as possible.Hope this helps.Dr. Joseph