How long does the burning during urination last?

Hi, I had oral sex with a new partner a couple times, about two weeks after the frist time I started really itching , some redness around the head of my penis, and some mild burning when urinating. I went to the doctor, he ran a urine test said no sign of infections, he ask about sexual partners and I told him i had been with a new partner, did not tell him it was only oral sex, as he did not ask, not sure if that matters, he put a swab in my penis for a culture, was going to test but said he would treat me with doxycycline 100 mg twice a day for 10 days, said this will take care of Chlamydia or ghonorriea which ever it might be. Well after he put that swab in my penis..which hurt really bad, it has hurt worse every time I urinate..I am now on day four and still some buring but it is back to about where it was when I went to the dr. it was much worse, I assume from the irritation from that swab, should i be concerned if the burning is not gone by now, or when should it be gone. I do notice if I drink a lot of water it does not burn as much ..in fact not much at all, but when not drinking as much water then it still burns quite a bit..thanks.

[2terrified]

Getting an std from oral sex is not that common at all.  You should continue to drink lots of water while taking the medication to help flush things out.  If symptoms are still there a week or two after finishing the medication, you should follow up with your doctor.