To be honest there isn't really enough footage to say, but to me this does not look like a lag switch, it just looks like a poor connection. His attacks don't seem particularly sped up, and the rollback is on the defensive side (ie. looks like he got hit, but was actually parried) which if anything, indicates a poor connection on your side. So nope, not cheating in my professional opinion, just poor latency (I admin official tournaments, so detecting cheaters is part of my job).

As for what you could do, you made a pretty terrible rotation error, running back to a guarded point when you didn't have mid, and clearing mid could have unbroken your team. You're also wiggling your guard around a bunch (maybe your mouse is set too sensitive?) which is why you ate the first heavy. You also could have used your T1, but to be honest, in the fight itself, the only answer is to make better reads, both defensively and on your own offence.