かえって

The word かえって can be used in a sentence when a result occurs that is contrary to your expectations. Though it can be translated literally as "on the contrary" or "rather", that often doesn't fit well into English sentences.

頭が痛かったので薬を飲んだら、かえってひどくなったしまった。
When I took some medicine since my head hurt, my head instead became worse.

急いでいたのでタクシーに乗ったら、道が混んでいて、かえって遅くなってしまった。
When I hurried so I could get a taxi, the road was crowded, and so I ended up going even slower.

よく切れない包丁はかえって危ないよ。
A kitchen knife that does not cut often is actually dangerous.

友達と大げんかをしたら、その後、かえって仲良くなった。
When I got in a huge fight with my friend, afterwards, we actually became closer.