I am a 15 year-old female who is experiencing lower abdominal pain/vaginal pain after urinating. Also, there is spotting of blood (red) on the toilet paper afterwards. The blood does not stain on my underwear, only appears when I wipe. As well as the pain-ONLY after I urinate. Please answer!

It sounds like a urinary tract infection for which you will need medication, but regardless go to the doctor asap. Chlamydia can have the same symptoms.

You need to see a doctor. Chances are that this will only get worse if left untreated.

This can be many things, also are you sexually active, is so, it adds many more possibilities.
But in general with pain urinating, you should go to your doctor for an exam

I get this literally every time I have sex. It sucks. I've done a lot of research and I'm pretty sure it's a UTI. It's probably a good idea to see a doctor, but for immediate relief, go to a drug store or supermarket and get Cranberry or AZO tablets. Those really helped me!