Conte, who returned to the touchline in Spurs' defeat at Leicester City on Saturday after recovering from gallbladder surgery, takes his injury-hit team to the San Siro on Tuesday.
"Playing Premier League and Champions League and also FA Cup will be really difficult," he told a news conference.
"At the same time we have to avoid another injury. Otherwise we will be in trouble," the Italian added.
Spurs have lost captain and goalkeeper Hugo Lloris to a knee ligament injury that will keep him out for at least six weeks.
Midfielders Ryan Sessegnon, with a hamstring problem, Rodrigo Bentancur, who tore knee ligaments after scoring in the 4-1 defeat at Leicester, and Yves Bissouma, following surgery on Friday for a stress fracture in his left ankle, are all out.
"In the last seven days we have had four serious injuries. For this season I think staying together is very important and trying in this kind of situation to create the right spirit," Conte said.
The 53-year-old, who was himself sidelined after being diagnosed with cholecystitis and having an operation to remove his gallbladder, said the situation was tough but he was looking for a solution "at home" for his lineup away to Milan.
"We're talking about two young players, Skippy (Oliver Skipp) and Pape Sarr. (It's) their first game in the Champions League, they are very young, 22 and 20 years old," Conte said.
"Especially for this reason we have to be good to help them overcome the emotion, and then we trust them."
Milan ended a seven-game winless run in all competitions with a 1-0 home victory over Torino on Friday and coach Stefano Pioli hopes the Champions League will lift his side.
"It's inevitable we suffered those negative results and the victory over Torino boosted our morale," he said on Milan TV. "Aside from that, when the Champions League comes along, it’s the Champions League. It doesn’t matter what form you're in.
"If we're playing at this level, it means that we are strong and so are Tottenham, so we must try to do better starting from tomorrow night."
