NASA was prepared to abort up to two landings before a successful one, and in fact they expected a failure during Apollo 11 (that thankfully never materialized). So, they'd go through a grilling, a few Service Modules get moved about in the schedule in a desperate effort to have Apollo 12 ready for liftoff by December. That launches successfully, Pete Conrad is the first on the Moon rather than Neil Armstrong (who, together with Aldrin and Collins, might get bumped to Apollo 17). Hopefully, the first words on the moon are not "Yippee," Conrad's OTL first words on the Moon.
Assuming that Apollo 12 is similar to OTL Apollo 11 in terms of achievement (a few hours on the Moon, proving the LEM ready for surface operations) and 13 does not experience significant problems (given that the troubled Service Module is, TTL, used in Apollo 11), NASA still gets to fly 2 "H" missions to the Lunar surface, and most likely 2 "J" missions. If the congressional hearings that result from the Apollo 11 crisis are not as bad as I make them out to be, they fly just as many Lunar Surface missions as IOTL, with the only major changes being that Pete Conrad walks on the Moon first, Jim Lovell and Fred Haise walk on the Moon at all, and the Apollo 11 crew are split up and put back into rotation for Apollos 17-19, in which case they'd be lucky for one of them to walk on the Moon.
Then there's the pessimistic scenario: NASA and congress panic in 1969 and limit the remaining missions to a first landing, one H-class (1 day stay), and one J-class (3 days, plus lunar rover) mission, to reduce risks. Apollo 14 is the last manned lunar landing of Apollo, in 1971, with the crew of Apollo 14 bumped off and Apollo 15 replacing it entirely, with the exception of the number. Alan Shepard never walks on the Moon, nor do Gene Cernan or Harrison Schmidt or John Young.