El Paso County Public Health requires a temporary-event license for body-art conventions. The event coordinator must submit the event application, supporting documents and fees before the event; the county's current Body Art page says to file no less than 30 business days before the event. The permit is event-level, so confirm with Villain Arts that the convention filing covers your booth before treating booth acceptance as permission to tattoo.
El Paso County defines a temporary body-art event as lasting no more than seven consecutive days. Current county guidance requires body artists to keep First Aid, bloodborne-pathogen and Hepatitis B documentation onsite, and the temporary-event rules require recent infectious-disease-control training plus affiliation with a body-art establishment licensed in the artist's home jurisdiction or qualifying sponsorship by an El Paso County licensed establishment. A pre-opening inspection is part of the event-license process.
Booth approval and legal permission to tattoo are separate. Use the state guide as a starting point, then follow the event-specific regulator or organizer filing above.