What is difference between skinny look and skinny appearance ?
These days l lost my weight but I do not like my skinny look.
These days l lost my weight but l do not like my skinny appearance.

Question

What is difference between skinny look and skinny appearance ?
These days l lost my weight but I do not like my skinny look.
These days l lost my weight but l do not like my skinny appearance.

Answer

Better yet, "I recently lost weight but I don't like how skinny I look." or
"I'm losing weight these days but I don't like how skinny I look."

You don't typically use "these days" for something that has already happened. Use present progressive ("-ing" form).

Answer

You'd say "These days I lost weight but I don't like how skinny I look."
"my skinny appearance" is ok but "how skinny I look" is more typical.
"I don't like my skinny look" is awkward.

Also "I lost weight". "I lost my weight" is incorrect.

Answer

Same meaning.  Your look is your appearance.

Answer

It would be helpful to have a sentence for context. In definition they both mean the same thing but context can change the idea conveyed.

Answer

I think they mean about the same thing.  Would you give an examples of use in a sentence?

Verpassen Sie nicht die Gelegenheit, bequem von zu Hause aus eine Sprache zu lernen. Stöbern Sie in unserer Auswahl an erfahrenen Sprachlehrern und melden Sie sich jetzt zu Ihrer ersten Unterrichtsstunde an!