The Portugal international has struggled for consistency since his summer arrival from Porto.
Gomes told Sky Italia: "Unfortunately, the team is not doing well and an attacker needs the team to play well and create opportunities.
"It is his first experience abroad, Italian football is different from Portuguese, especially at a tactical level.
"He is making a bit of effort, but it is a matter of adaptation. He is great and will score many goals too in Italy, as well as doing the same internationally."