More than likely, that is the LCD's "blood". Your LCD probably leaked. I didn't have that problem. Mine was dry but the gorilla glass was shattered. I have not had to replace mine again in nearly a year. Just be careful!
Samsung Galaxy Note 3 SM-N900A Rooted with 64GB Cl.10 External SDXC (Currently)
Samsung Galaxy Note GT N7000 White & Rooted with 32GB Cl.10 External SDHC (Formerly)
Dell Streak 5 running Simple Streak 1.2 PerfUpdate + OC 1.190GHz (Formerly)