入っちゃった

ended up entering; got in

→ 入る
入っ enter, go in + ちゃっ Completive (often regretful or accidental) + Past tense
verb · past indicative Rare #40,744
ended up entering; got in Colloquial contraction of 入ってしまった, often implying that the action was unintended or has been completed.
JA: 間違えて知らない人の部屋に入っちゃった。
EN: I accidentally ended up entering a stranger's room.
Conjugation of 入る

の中に入っちゃった

A pebble got inside my shoe.

入っちゃった

I got sand in my shoe.

目に砂が入っちゃった

I got sand in my eye.

間違えて人の部屋に入っちゃった

I accidentally walked into someone else’s room.