Charges p99 latency spikes

It's 14:10 and you're on call for the payments API (Java/Spring Boot, Postgres via HikariCP, behind an ALB). PagerDuty fires: p99 latency on POST /charges jumped from 180ms to 2.4s, while p50 is unchanged at 60ms. Error rate is flat, nothing is failing, requests are just slow. The Hikari dashboard shows connections.active pinned at the pool max of 20 and connections.pending climbing into the dozens. Postgres pg_stat_activity shows ~20 sessions, most in state idle in transaction. A deploy went out at 13:55 that 'added an external fraud-score lookup before committing the charge.' Walk me through how you triage this and what you do in the next 15 minutes versus the next week.