Hello there...yes you require medical attention...a decayed tooth involving the pulp would initially be painful....At times when the tooth becomes non-vital the pain subsides...but the infection spreads to the apical part of your tooth...As the necrosed material of your tooth gets accumulated within it, it progresses to abscess
.... abscess is nothing but the localized collection of pus... Only when the abscess starts becoming bigger the pus within spreads to the adjoining spaces and starts showing up on your face...the pus has to spread at the cost of bone resorption
and compressing the adjacent tissues...that is when you would have pain...before it progresses to the space infection get yourself treated.... The treatment would be in the form of root canal
or extraction... Consult your dental surgeon for clinical evaluation and management...