My Wife And I Are Having Problem When We Attempt

My wife and I are having problem when we attempt to have oral sex.

We got married 6years back, in initial stages of marriage. We use to have oral sex frequently and enjoys it without any problem..... But recently, my wife is having severe throat pain and slight feverish after performing the oral sex..
.is there is any remedy in order to avoid pain and to lead a happy sexial life.