painful blisters on finger

RIGHT BEFORE I GET SICK WITH A COLD OR ANY KIND OF SICKNESS I ALWAYS GET A BLISTER ON MY RING FINGER OR THE FINGER BESIDE IT. IT STARTS OUT AS JUST A FEW LITTLE BUMPS THAT ITCH BUT THEY GROW INTO ONE BIG BLISTER THAT HAS FEVER,FLUID AND BLOOD AND IT WILL MAKE A RED PATH DOWN THE TOP PART OF MY HAND UNTIL I BUST THE BLISTER. IT WILL HURT FOR A FEW DAYS BUT THAN I GOES AWAY A FEW DAYS AFTER I BUST THE BLISTER DOES ANYONE KNOW WHAT THIS IS IT ONLY COMES UP ON MY LEFT HAND AND MOSTLY ON MY RING FINGER.

                                                                              MARIA