Hey guys, thank you all for the answer. Little guy is fine, maybe it were just some cricket guts as Grif mentioned.
He's eating well, burrowing during day coming out at night. I guess i'll stop worrying about this it's been a while, and if he was in pain he would not eat and it's not the case. He has just eaten 3 crickets.
I think he's been sheeding, is skin is beautiful those days

Thank you all for your answer guys!