Bump on septum two weeks after septorhinoplasty?

After two weeks, that bump that you are describing could be any of those options. Swelling, scar tissue, suture material, etc. are all reasonable culprits that should improve with time. I would bring it to the attention of your surgeon on your next office visit.

Thank you for your question. 
With any nasal surgery, the name of the game is patience. At one week, we would expect you to have quite a bit of swelling and bruising still noticeable and may have trouble breathing out of one or both nostrils. By the end of two weeks, typically, you will still be swollen but look more like you have a bad cold, rather than post surgical. Swelling can take up to a year to be completely gone, however, by 9 weeks you will look very good and should see big difference from your pre-op pics.

yes it can be any one of those things, but it is not something to worry about now. You are healing and have swelling both on the inside and outside of your nose, and that's normal. Follow you surgeon's instructions and be patient.