Never buy views. It's against the rules.
I see you got these views from your last video. Wait a few days until the stats are released over this video. There is no hard panic yet. But if you do get bots turning off the possibility to view trough mobile devices might help.
For now wait until the stats are released and see where the traffic comes from from that video.
-It's possible that your video got featured somewhere.
- Also possible a bigger youtuber liked the video and you got a small boost of viral views.
- If botted you will get thousants of views in a few day's. (This might be a small bot campaign but no big worry yet. )
- Could be fault of YouTube, They might still adjust the views happens a lot lately.
You will notice a -xxx amount of views on socialblade like seen on my page:
http://socialblade.com/youtube/user/skenkee