These are called Cherry Angiomas they are harmless overgrowths of blood vessels, (capillaries, small veins), fragility. In my experience they can indicate low or sluggish lymphatics in the area they appear.
They do not cause any symptoms but may bleed due to friction or trauma, particularly if you wear strong compression, tight bras, or rub on your inner thighs, knees, or upper arms. As the name suggests, cherry angiomas appear as tiny cherry red domes measuring between 1 to 4 mm in diameter.
They can be linked to some conditions like Lipoedema and Lymphoedema and Pregnancy due to hormonal changes and can increase with age.
If you scratch them and they start to bleed it may take some effort to get the bleeding to stop as capillaries have a tendency to be heavy bleeders. They can be excised and cauterised by a Doctor if you really don't like them or I just leave mine alone and am vigilant on what rubs against them.