Hymen and oral infection

I m a 21 year old girl,i am in a rellationship from past 2 years.we
indulge in sexual activities like oral sex.we enjoy quite a healthy sexual
relationship however we have never had intercourse nor we intend to do
it before marriage.
I would like to discuss some issues Last night he had licked my vagina
for a long time and even fingered a bit but only on my clitorus.Later
on i saw some blood coming out of my vagina.I am not sure whether it was
due to licking or  was it becasue it was my fifth day of menses.
This blood was red blood in color and dint smell like normal menses
blood.This bleeding stopped later on.
I think since i am not able to see my hole it means the hymen is still
covering it and my hymen is intact..
I dont think my bf went too deep while licking, but still i am really
worried that is my hymen torned?can u please tell me how does one come
to know whether their hymen is intact?Does it pains when Hymen breaks?
I have examined my vagina there's no difference,I still cant figure
what's hymen?and how does it look like?
There's one more problem which i would like to ask,whenever i suck my
bf's penis next day it starts paining in my throat.
it appears to be as some pimple like things develops on my throat.I
went for a checkup but doctor said that they are tonsil however i cudnt
confront to her that i have had oral sex.Is it some infection or a std?