Yes the word LIKE makes it a simile. IF the verse said his sweat WAS drops of blood then it could EITHER be interpreted as a metaphor OR literally (which is to say that his sweat was mixed in with blood as several physicians have documented in actual medical cases). The word LIKE statesmakes it a more comparative statement VS a more literal XOR open interpretation. (for those of you who have used the & OR function to Google things in the wee hours of the night:)