Frankly... if the Indians are stupid enough to do something like that no amount of PR offensive will save them... they will be the ones escalating and basically declaring war with an attack on a civilian target at that, the Chinese would have every right to retaliate and the public would probably demand a response... if the Indian news media didn’t jump the gun and started the media campaign about the Chinese building a village before hand they can still lie and claim the target to be a military installation...Or, in response to Joe Biden's inauguration, launch an artillery strike on that location, at the same time go full-on PR offense globally to get US onboard, go maximum pressure on China.
You see, members of the Biden Administration has set the tone for Sino-US relations in the next 4 years, pointing at the direction of further escalation on the foundation built up by the Trump Administration, thus India actually has an opening there, all that is needed is some resolve on New Delhi's part.
Question is, can Modi got the courage to pull that off?
The US whatever they think will have no right to intervene, especially now with a brand new administration, dragging the country into a war with a near peer because your ally decided to bomb a civilian village isn’t exactly what you want to be remembered for in your first month on the job, we are not talking about some country in Africa or Middle East that don’t have the will or arms to response here and by the time the US work up the courage due to development on the ground to use more then just words or something additional to lip service and fabricated a casus belli it would have likely passed the 15 days the Indians expect their ammo stock to last in an intense war and probably would have surrendered already...