If you re-enter the Kingdom by land, you'll need to get another visa, unfortunately, because you're not from one of the countries blessed with visa-free entry.

But if you fly back and don't pass through Immigration because you have a connecting international flight, then there's no visa question. You're simply in transit.

Since you also have your return ticket to India, there's also no chance the airline will refuse to carry you. At Don Muang, the transfer personnel were in the passageway just before Immigration. I imagine it's the same arrangement at Suvarnabhumi. I've never done this at BKK, but I read somewhere that they go and get your baggage off the belt for you and put it onto your connecting flight if you were not able to check your baggage through.

The only country I know which insists you pass through Immigration even if you're just transferring to another international flight is the United States. Perhaps there are others.