I checked the spelling mistakes and I reworded some of the sentences. Can you please check them and tell me how I can improve them? Thank you.

1)Dorian throws himself on the sofa, and starts thinking of his past. He recognizes he has filled his mind with corruption, committed horrible crimes, and exerted an evil influence on others.
2) He admits beauty and youth have only caused his ruin. In particular, beauty has been but a mask to him and youth but a mockery. (how can I reword this?)
3) Then he remembers Hetty, the beautiful and charming country girl, whom he met in a village and had a romance with.
4)They were going to elope together but he eventually spared her so as not to ruin her reputation.
5) He was well aware that their elopement would have meant the girl's ruin by Victorian standards.
6) Now he cheers himself by thinking of this recent good action and wonders if the portrait has changed (for the better).

1)Dorian throws himself on the sofa, and starts thinking of his past. He recognizes he has filled his mind with corruption, committed horrible crimes, and exerted an evil influence on others.

delete the comma after "sofa"

2) He admits beauty and youth have only caused his ruin. In particular, beauty has been but a mask to him and youth but a mockery. (how can I reword this?)
delete "only" - you could write, "beauty and youth have been only temporary conditions"

3) Then he remembers Hetty, the beautiful and charming country girl, whom he met in a village and had a romance with.
... and with whom he had a romance.

4)They were going to elope together but he eventually spared her so as not to ruin her reputation.
comma after "together"

5) He was well aware that their elopement would have meant the girl's ruin by Victorian standards.
OK

6) Now he cheers himself by thinking of this recent good action and wonders if the portrait has changed (for the better).
OK