Baby boa not eating

[Guy234]

Excuse me but recently I have gotten a baby red tail boa, a little more than a week ago to be exact. Though I’ve have him and offered him a lot of food, he seems very frightened by the food. He moves around the enclosure a lot also like he’s hunting. I’ve put my finger up to the glass and his tong flickers very fast and he almost chases it, but as soon as the top comes off he gets very frightened. I’ve held it in from of his face and his tongue starts going, but as soon as he gets close enough and smells it he just backs down. The only time he ever took the food was like 3-4 days after I got him. He tools it in his mouth but I made a mistake and tried to put the lid back on and he got scared and let go. I’m not sure if he’s ever eaten before as I bought him offline from underground reptiles. I’ve tried braining the mouse, leaving it in there over night, and even chicken broth, nothing has worked. The hot side of his 20 gallon is around 90 degrees and I spray it twice a day. Please give me any ideas. Oh and one more thing I haven’t tried feeding him every day so I don’t stress him out too much, and I covered all sides of his enclosure except the front. Please help.