“Shh, Lois,” he cooed, trying to calm her with his voice and with his arms even as he wondered what had happened to upset her so. “Tell me what’s wrong.”
He doesn't get it. I am surprised he thought he could be gone this long and not have people notice. ALthough, maybe he lost track of the tiem.
Lois pulled back to look at him, framing his face with her hands. She opened her mouth to speak, but seemingly thought better of it. Instead, Clark caught a glimpse of the famous Lane determination in her eyes just before her lips crashed down upon his.

They are kissing.
Lois:I am not going to let that squatter Mayson try to stake her claim again. These lips are mine I tell you.
Shocked by the move, he didn’t respond at first. Undeterred, Lois slid her hands into his hair and teased his bottom lip with her tongue until he managed to follow her cues. His lips parted under her sweet sensory assault, and his first true taste of her sent waves of desire cascading through his body.
He was so attuned to her that he swore that he could feel the emotions that swirled within her and spurred her to action. Her passionate joy was tempered by a fear he could not name, but he could sense her heart opening to him. Her trust was a precious gift, and he tried with each touch to communicate the depth of his love for her.
I guess this is an expected reaction of Lois on finding him. Although I still expect her to want an explanation soon.