Bhai Jagjit Singh Jio,
Gursikh has a great Bharosa that
ਹਰਿ ਬਿਨੁ ਕੋ ਮਾਰਿ ਜੀਵਾਲਿ ਨ ਸਾਕੈ ਤਾ ਮੇਰੇ ਮਨ ਕਾਇਤੁ ਕੜਈਐ ॥1॥ ਰਹਾਉ ॥If a poisonous snake bites then still it is in hands of Akal Purakh to save one or end the swaas. Snake is to blame in case of death becuase due to previous Karams there is something to pay off that snake.
In regards to Vanjara people, they have skill (some others too) to suck snake poison from body. There is nothing wrong getting treatment from them if they are in reach.
Daas doesn't know any different Mantar for snake bite but there is one procedure that is used on all other bites, i.e. sting from bees/bugs and etc. Didn't try with snake bite yet but no harm to try if someone wants to. This can be tried until a conventional medical treatment arrives or not possible.
Original Mantar used in this procedure has a couplet which asks a King to devoid the bite reaction. I tried before and seems workable but then Gurmat thought took over the precedent that no Mantar is above Gurmantar. But Gurmantar can't be told to anyone if asked by someone for this procedure. I would say use Moolmantar instead and it works. ਪੰਜਾਬ ਵਿਚ ਤਾਂ ਭੂੰਡੀਆਂ ਜਾਂ ਖੱਖਰਾਂ ਦੇ ਡੰਗ ਦਾ ਅਸਾਨ ਜਿਹਾ ਹੀ ਇਲਾਜ਼ ਹੋ ਜਾਂਦਾ ਸੀ।
Here is the procedure:
1) Locate the bitten place precisely.
2) Remove your Sarabloh Kara.
3) Rub Kara over the bitten place (sting) in one direction (possibly opposite to the sting direction). Don't worry if you can't figure out the direction, just make sure Kara has to be rubbed in one direction only. Not back and forth.
4) Do five Moolmantar Jaap while rubbing.
5) Say Fateh at the end and then you should be sting free.
Note: Above is not a medical treatment or professional advise. Use at your discretion with faith.