I've trekked the whole Annapurna circuit and its max altitude is about the same EBC IIRC. Really, it hurts a bit for a little while but getting tattooed hurts more in comparison to what you are doing and seeing. Also, the more you stays there the less it hurts or affects your body (I have spent 40 days in the mountains). Machu Picchu is nothing compared to Nepal's mountains, go for it! You won't regret it :-)