I stamped my passport with an unofficial stamp in Peru, will this cause a problem attaining a visa?

I travelled to Peru last summer and visited Machu Picchu where i foolishly stamped my passport with a novelty souvenir stamp. At the time I was very worried that I may have invalidated my passport, however I was able to leave the country and pass through the USA with no issues and since then I have also visited Turkey and the USA, again with no problems. My girlfriend and I are now planning on travelling to China for three weeks this summer and the entry requirements seem slightly more serious than the other countries I have visited. I am worried that when I send my passport off in order to attain the entry permit, this Machu Picchu stamp may be picked up on and may stop me from getting it. Will this be the case or do I have nothing to worry about?