i'll have to agree. however, i am pretty sure a lot of noobs is going to chime in with a bunch of their misdiagnosing assumptions and turn this thread into 40 pages of nothing. before they do, i suggest you take Ogrebs advise and continue doing as you've been doing. gl.Your just freaking.
The water mark looks like nute splash. Or it's just one of those leaves that all plants get.
All I see is a node, bump..pre calyx ?
Otherwise all I see is a very healthy plant with one wanked leaf.
Just take a toke and chill..
Peace