I am getting approx 500 marks in neet. From general category. What to do now??

In general, first to qualify in NEET, a General Category candidate has to score 50% of the top NEET score. It is 40% for SC, ST, OBC. For example, if the top NEET scorer has scored 500, General Category candidates should score atleast 250 and SC,ST,OBC should score around 200 to qualify. Now not every qualified candidate can get a medical seat. It depends on cut offs. Now cut offs change every year and are dependant on various factors like no.of seats available, no.of candidates appearing for the exam, difficulty of the exam and top NEET score. Every State except Jammu and Kashmir has All India Quota and State Quota and there is different cut off for each quota. Now every State has various cut offs for every college and Category. Tamilnadu is one of the States with highest cut off. But States like Assam do not have that high cut off. So it totally depends on what State you want to apply and if you want to apply under All India Quota or State Quota. State Quota has higher cut off marks. For Tamilnadu, it should be atleast 625. But for Himachal Pradesh it is around 300. And you cannot be eligible for State Quota of every State which means you should also try for All India Quota. But without having an idea of which State you want to apply for, it is difficult to guess your chances. For example, with the cut offs that Tamilnadu has, one can easily get a seat in a Govt. Medical college in West Bengal

You haven't mentioned  the State that you want to apply for. So it totally depends on what State you want to apply and if you want to apply under All India Quota or State Quota. State Quota has higher cut off marks. Neverthless, anything less than 550 in General is less. For Tamilnadu, it should be atleast 625. But for Himachal Pradesh it is around 300. For Karnataka, the highest cut off was 512. And you cannot be eligible for State Quota of every State which means you should also try for All India Quota. But without having an idea of which State and Category you belong to, it is difficult to guess your chances. But in general 515 is a score that can give you the best colleges. You have fair chances in states like Maharashtra, UP if you have their State domicile.

Lets first look at what was the cut off in previous year (General category)
AIQ Cut Off -

Govt. Medical College, Kozhikode - 632
Govt. Medical College, Kottayam - 599
Govt. Medical College, Thiruvananthapuram - 614
Govt. Medical College, Thrissur - 595
Govt. Medical College, Ernakulam - 589
TD Medical College, Alleypey - 593
Govt. Medical College, Kollam - 563
Govt. Medical College, Manjeri - 585
Govt. Medical College, Yakarra - 581
State Cut Off -

Govt. Medical College, Kozhikode - 583
Govt. Medical College, Kottayam - 597
Govt. Medical College, Thiruvananthapuram - 608
Govt. Medical College, Thrissur - 590
Govt. Medical College, Ernakulam - 583
TD Medical College, Alleypey - 583
Govt. Medical College, Manjeri - 584
Seeing at these cut offs and keeping in mind, cut off varies from year to year, I would suggest you to score 600+. 600+ would be a safe score with which you can obtain a Govt. Seat in Kerala under General/Unreserved Category.
For complete details visit - https://medicine.careers360.com/articles/neet-cutoff-kerala

According to the data, and your marks it's possible to get a government seet, but not guaranteed

You can try a private college also

Hope that helps!!