I went to the orthodontist and got braces tightened. a red bump formed behind my top front teeth. slightly painful great oral hygene

Inflammation: Sounds like inflammation possibly related to ortho treatment. See dentist or orthodontist for assessment.

Transit irritation: It is more common in the upper jaw. Start rinsing your mouth with a warm salt-water rinse 2 times per day.

Incisive papilla: Covers the spot where vessels and nerves exit upper jaw & spread over palate. Tooth movement may be pinching these tissues. Have Orthodontist check tissue. Make sure you brush area gently 2x/day. Clean between teeth (floss or Water Pik) daily. Take analgesics as needed.