The dimmer switch is a lot larger than a regular single pole switch. Its possible when you pushed the dimmer into the box you knocked the neutral wires or a hot wire junction loose. Pull the switch and inspect the other wires in the box. There maybe multiple wires coming together in that box. Hot feed in, hot feed out to other switches and the wire to the light. All of the neutrals(white) will be together in a wire nut. The hot in and out will either connect to one screw or wire on the switch or will be together in another wire nut with a spare wire to switch leaving the power to the light on the other screw or wire to dimmer. Grounds are together also. Remove the switch and check the connections

It gets way more complicated if they were 3 way switches (two switches controlling one light)