The latest aftershock had a magnitude of 5.9 or 6.2, according to monitors. It brought down some buildings.
Rescue workers are still digging through rubble and trying to get aid to survivors of the earlier, larger quake.
The Red Cross says that incident, which was magnitude 6.9 and killed at least 131, was “exceptionally destructive”.
Some villages had “completely collapsed”, said a Red Cross official in Lombok, Christopher Rassi.
While the official death toll from national authorities stands at 131, provincial officials say 226 people have died. Local media are reporting figures as high as 347.
The government says more than 1,400 people were injured and more than 156,000 displaced.
The national disaster agency has said all those numbers are likely to increase, as more information comes in and more victims are found.
The new tremor hit off the north-west coast of Lombok, sending people running into the streets in panic. No tsunami warning was issued.
‘I ran as fast as I could’
By Mehulika Sitepu, BBC News, Mataram
More than 350 aftershocks have struck since the quake on Sunday. Usually it feels like the ground is gently swaying. But Thursday’s aftershock was different.
In my third-floor hotel room in Mataram, the island’s capital, windows smashed, walls cracked and the ceiling started to collapse.
I ran as fast as I could, barefoot, taking nothing with me. The stairs shook as I ran from the building into the street outside, where people were crying. Their fear was clearly visible.
Sturdy buildings such as my hotel, in the north of Lombok and 13km (8 miles) from the epicentre, can withstand such shocks. But the rickety houses where many islanders live cannot. This is why so many people here are now homeless.
Disaster agency spokesman Sutopo Purwo Nugroho classified it as an aftershock. A British tourist on nearby Bali told the BBC that it had been felt there, causing people to leave their hotel rooms in the southern resort area of Seminyak.
Emergency workers are gradually starting to reach more remote areas of Lombok as they continue their rescue missions.
But Mr Sutopo said some areas in the north had still not received any aid.
Masih pengungsi yang belum tersentuh bantuan untuk korban gempa di Lombok khususnya di Lombok Utara dan Lombok Barat. Kerusakan bangunan masif di Lombok Utara. Perlu upaya keras untuk segera menyalurkan bantuan. pic.twitter.com/nHheUGMLny
— Sutopo Purwo Nugroho (@Sutopo_PN) August 8, 2018
Lombok is a roughly 4,500 sq km (1,700 sq miles) island east of the slightly larger island of Bali.
Most people live in basic housing in small communities. Tens of thousands are now sleeping out in the open or in the ruins of their homes.
“We are still waiting for assessments from some of the more remote areas in the north of the island, but it is already clear that Sunday’s earthquake was exceptionally destructive,” said Mr Rassi.
“I visited villages yesterday that were completely collapsed,” he added, while other teams in East and North Lombok had reported villages where 75% of homes were damaged.
With hospitals and clinics also affected, many of the injured have had to be treated in the open air or in makeshift clinics.