Valero, who joined Inter in 2017 after five years at Fiorentina and has the coordinates of the city tattooed Online Cigarettes Store USA on his arm, didn't celebrate and instead raised his arm in apology.
Lautaro Martinez thought he had doubled Inter's lead with his sixth goal in as many matches but it was ruled out as Romelu Lukaku had been marginally offside in the buildup.
Home goalkeeper Bartlomiej Dragowski also pulled off a great save to deny Lukaku as Inter failed to bounce back Newport 100s Box from its defeat to Barcelona and becoming the only Italian team not to progress to the last 16 of the Champions League.
''Just like against Barcelona, we got less than we deserved,'' Inter coach Antonio Conte said. ''It's disappointing because today the team responded well after Tuesday's defeat.
''It's a process of growth and we have to all be patient, because we're still not in the conditions to win every match just because we're called Inter.''Hellas Verona fought back from three goals down to draw 3-3 against Torino.
Torino was 3-0 up after an hour but all three Verona substitutes scored in a 15-minute spell to secure an improbable Cheap Newport 100s cigarettes point.
Atalanta was surprisingly beaten 2-1 at Bologna, which had defender Danilo sent off two minutes from time.
Atalanta remained sixth but fell four points behind the Champions League spots after Roma fought back from a goal down to beat bottom-place Spal 3-1.
Cagliari can move back into fourth if it wins at home to third-place Lazio on Monday.
Rafael Leao hit the woodwork twice late on but AC Milan drew 0-0 against Sassuolo.