I got 138marks for neetandI have 45858 kerala rank there is any chance to get a merit seat in neet offered any professional courses

Hello,
As you mentioned with 138 marks, your chances of getting a decent government college anywhere are negligible.As your marks are too low you might not even get some private medical college.
I suggest you to go for some other course or prepare for NEET next year.
Or you can go for management quota seats in private colleges but fees would be more than 40 lakhs for it.
However cutoffs change every year depending upon level of toughness of exam. So hope for the best and follow the counselling process.

Follow this link to better predict your college-
https://medicine.careers360.com/neet-college-predictor
Good luck